On the heels of Tuesday's narrow Republican win in Arizona's 8th district, we have an updated outlook and some ratings changes from the forecasters at Sabato's Crystal Ball. Ratings changes were made to 15 districts, including 10 new races that moved from safe to likely Republican.

In their own words:

"Overall, our House outlook remains the same: Democrats are about 50-50 to win the House. What these ratings change do is make clear that in the event of a big wave, there are some districts that might not seem competitive on paper that could flip, particularly because a deep bench of Democratic candidates is in place to capitalize on a potentially great environment in the fall. That’s where one could see Democrats picking up substantially more than the 23 net seats they need to win House control. However, the Democratic wave could fail to materialize, and Democratic gains could be limited to the teens. At this juncture, the range of possibilities in the House is wide. We realize that may be an unsatisfying and overly cautious assessment, but that’s where we’re at right now with the election still half a year away."

As most of the shifts were from safe to likely Republican, the overall forecast changes little, although the map isn't quite as dark red as it was. Republicans are favored in 211 seats, Democrats 198, with 26 toss-ups. 

Click the image for an interactive version. Note that we've added a 'Map Options' link, near the share buttons, below Florida. For those that don't want to rotate through as many colors when creating a forecast, you can choose a smaller palette there.

The latest ratings changes are in the table below. They include some high profile names. Read the full analysis for more background on these individuals and the rationale for the current rating.

Republican Debbie Lesko won the Arizona 8th congressional district special election Tuesday, defeating Democrat Hiral Tipirneni by 5 points.

While the GOP prevailed, Democrats outperformed history and expectations in this conservative district. This continues a trend that has occurred in every special election since 2016. In this particular district, the prior incumbent Trent Franks won reelection by 37% that year, while Donald Trump bested Hillary Clinton by 21%.

Once Lesko is sworn in, there will be 237 Republicans and 193 Democrats, with 5 vacancies. These will be filled as follows:

• June 30: TX-27,  (prior incumbent) Blake Farenthold (R)
• August 7: OH-12, Pat Tiberi (R)
• November 6: MI-13, John Conyers, Jr. (D)
• Date TBD: NY-25, Louise Slaughter (D)
• Date TBD: OK-1, Jim Bridenstine (R)

At this point, only OH-12 looks competitive. The remaining districts are expected to stay with the incumbent party.

This New York Times page should be a good source of results from the special election for Arizona's 8th congressional district. Polls close at 10:00 PM Eastern Time; the first results expected around 11:00 PM.  According to the Secretary of State, these first results will be from early voting. This is expected to be a majority of the vote in the election, so it is possible we'll have an idea of the outcome at that time. Subsequent results - today's voting - are not expected until midnight or later.

See our article from earlier Tuesday for more information on the election.

Voters in Arizona's 8th congressional district will go to the polls today to elect a new congressional representative. The polls are open until 7:00 PM Mountain Time (10:00 PM Eastern Time; Arizona doesn't participate in Daylight Savings Time). The 8th district is entirely within Maricopa County*, and includes portions of the Phoenix metropolitan area.

The election pits Republican Debbie Lesko, a former state Senator, against Democrat Hiral Tipirneni, a physician.

FiveThirtyEight has a good overview of the election, including why a repeat of last month's Democratic win in the PA-18 special election is unlikely despite the fact that Donald Trump won both districts by about 20% in 2016. 

Much of the voting for today's election was cast during early voting. For those that are interested, the state provides a nice level of detail on the composition of those that voted during this period. While it doesn't tell us how people voted, about 75% of the returned ballots were from those over 55; the median age of all early voters is 67. Just under half the early voters are registered Republicans, compared to about 28% Democrats and 23% independents. 

According to the Arizona Secretary of State, the early vote counts will be released at 8:00 PM (11:00 PM ET), after which there will be a lull for an hour or more before counts from today's vote begin to be posted.

* Although Maricopa County encompasses just 8% of the state's geographic area, portions of it are included in all but one of the state's eight congressional districts. 

Oklahoma Republican Rep. Jim Bridenstine resigned from Congress on Monday. He was subsequently sworn in as the new head of NASA. Bridenstine had been nominated by President Trump for the position last September, but was only confirmed by the Senate last week.

Gov. Mary Fallin will need to call a special election to fill the remainder of Bridenstine's term. It is unclear if that will take place prior to the November 6th midterm elections. 

Bridenstine won a 3rd term without opposition in 2016 in a district that Donald Trump won by 29%. The oddly-shaped first district is expected to remain in Republican control.

There are now six vacancies in the U.S. House. One of those, in Arizona's 8th district, will be filled in today's special election. Republicans now control the house by a 236 to 193 margin. A full list of retirements and vacancies can be found here.

April 20th marks 200 days until the 2018 midterm elections, scheduled for November 6, 2018. There will be elections for all 435 House and 35 Senate seats. There will also be 36 gubernatorial races contested that day. 

The maps below highlight the races seen as more competitive at this time based on a consensus of forecasts from Sabato's Crystal Ball, The Cook Political Report and Inside Elections. Click/tap any of them for an interactive version. Links to a blank map are also provided.

House of Representatives

There are currently 237 Republicans and 193 Democrats, with 5 vacancies. A 6th vacancy is forthcoming as Rep. Jim Bridenstine (R, OK-1) was confirmed Thursday to head NASA. One of those vacancies, in Arizona's 8th district, will be filled in a special election on Tuesday. If we assume all the vacancies stay with the incumbent party, Democrats will need to gain 23 seats on November 6th to take control in 2019. There are currently 65 seats rated toss-up or leaning by one or more pundits. Those are shown as tan on the map below. A blank House map is also available.

Senate

Republicans currently have a 51-49 edge over Democrats, who need to gain two seats to take control in 2019. There are two special elections among the 35 races this year. Eleven seats look to be most competitive, with six of them rated toss-up by all three pundits.  These include Republican-held Arizona and Nevada, along with Democratic-held Florida, Indiana, Missouri and North Dakota. Democrats hold 26 of the 35 Senate seats, including five seats that Donald Trump won by 18% or more in 2016. 

The battleground map is below; a blank Senate map is also available.

Governor

Republicans sit in 33 of the 50 governors' chairs, while Democrats hold of them. Alaska governor Bill Walker is an independent. 36 seats will be contested in 2018, of which 16 look to be competitive at this point. Most of the governors elected this year will be in office when redistricting occurs after the 2020 Census. As a result, these state races have more national implications than usual.

The battleground map is below; a blank gubernatorial map is also available.

Rep. Charlie Dent announced he would resign from Congress "in the coming weeks". The Pennsylvania Republican, in his 7th term, had previously announced he would not seek re-election in 2018.

After discussions with my family & careful reflection, I have decided to leave Congress in the coming weeks. Serving the people of #PA15 has been a tremendous responsibility & the privilege of a lifetime. pic.twitter.com/p8mik6s8ix

— Rep. Charlie Dent (@RepCharlieDent) April 17, 2018

Pennsylvania Gov. Tom Wolf must announce a special election date within 10 days of a vacancy. Complicating matters is this year's court ordered redistricting in the state. Dent's 15th congressional district will largely become part of the new 7th district. However, any special election would take place using the current district boundaries, as these remain effective for purposes of representation until the new Congress is seated in 2019.

There may be a way around this - we don't know - but here's an interesting scenario:

Given the timing, from a cost perspective it likely makes the most sense to have this special election on the same date as the midterm elections. When these concurrent elections happen, the same nominees are usually on the ballot for both races, and thus the winner of the special election is normally also going to be the winner of the election for the subsequent full term. 

However, in this case, two different sets of voters would be involved on the same day - those in the current 15th district for the special election and those in the new 7th district for the full term. While the 15th district voted for Trump by about 8% in 2016, the new 7th district actually voted for Clinton by 1%. As a result, it is possible that the winner of the special election could lose the regular election and thus this person would only serve in Congress during the few weeks of a lame-duck session.

Democrat Conor Lamb has taken his seat in the U.S. House. Lamb won a special election in Pennsylvania's 18th district last month. He will complete the term of Republican Tim Murphy, who resigned last fall.

Lamb's win was an upset in this Republican-leaning district. With court-ordered redistricting, the 18th district will largely be absorbed into the new 14th district, which is even less hospitable to Democrats. As a result, Lamb is running for re-election in the new 17th district. He'll be up against Republican Keith Rothfus in a race that is currently seen as a toss-up. 

There are now 237 Republicans and 193 Democrats in the House, with five vacancies. The next one of those to be filled will be in a special election in Arizona's 8th district on April 24th. The winner of that race will complete the term of Republican Trent Franks, who resigned in December. That race is rated likely GOP. A just-released poll of the 8th district gives Republican Debbie Lesko a 53% to 43% lead over Democrat Hiral Tipirneni.

Click the map above for an interactive version of the 2018 House elections. Note that Pennsylvania displays the new district boundaries. To view current boundaries, use our elected officials lookup for Pennsylvania.

The Speaker of the House, Republican Paul Ryan of Wisconsin announced Wednesday he would not seek re-election in 2018. He is the 38th*, and most prominent member of the GOP to retire rather than face the voters in an election that may lead to a Democratic House majority in 2019.  The New York Times suggests that "it could also trigger another wave of retirements among Republicans... taking their cue from Mr. Ryan."

While not likely a major factor in his decision, Ryan was facing a more challenging race to hold his district than the one he won by 35% in 2016.  With his departure, Sabato's Crystal Ball moves the race from 'Likely Republican' to 'Toss-up'. The GOP has until June 1st to find a suitable replacement for Ryan on the ballot -- the only other Republican on the ballot at present is white nationalist Paul Nehlen.

Overall, Sabato currently has 193 seats as safe or likely Republican, vs. 191 for Democrats. Of the 51 remaining seats - those with the most competitive races - all but five are held by the GOP.  Democrats need a net gain of 23 seats to win control of the House.

Click the map to use these ratings as a starting point to create and share your own 2018 forecast.

* It was 37 when we started writing the article: Dennis Ross, a four-term Republican from Florida's 15th district, subsequently announced his retirement. Ross won re-election by 15% in 2016; Donald Trump won here by 10%. The race has moved from safe to likely Republican.

You can now save & share your 2018 House forecast. Use the interactive map to create your forecast, then click 'Share Map' to share it across social media. Alternately, use the Embed button to insert your map onto a web page or blog. For example, here's a map with the 50 races seen as most competitive*. Click it for an interactive version:

Click the map to create your own at 270toWin.com

For those that want to make their own forecast from scratch, we have a map that starts with all 435 districts undecided.

The House map was relaunched earlier this year with a number of new features, including pan and zoom capability.  The Senate and Governor maps have also been updated. We're getting close to our goal where all the various interactive maps will have roughly the same capabilities. There are 211 days until the 2018 midterm elections.

* These 50 seats are seen as toss-up or leans Democrat/Republican by Sabato's Crystal Ball as of April 9th