The votes from Tuesday's special congressional election in Pennsylvania are still being counted, but Democrats have already won the psychological battle. At the very least, they came close to winning a district President Trump won by 20 points.

Democrats' stunningly strong performance deep in Trump country can't be ignored as we look to November's midterm elections, where all 435 House seats are up for reelection. Voter enthusiasm, polling and high-profile GOP retirements indicate the House majority is up for grabs.

If Democrats win back the House for the first time in eight years, they'll do it by winning in districts like the 10 below. Nine of our 10 House races most likely to flip parties this November belong to Republicans, and they span the country.

Here they are, ranked in order of least likely to flip parties (10) to most (1). We'll revisit these semi-regularly leading up to November's midterm elections.

10. California's 39th District (open seat): GOP Rep. Edward R. Royce is retiring after 26 years. He had built a relationship with the district's growing Asian and Latino population, and now that he's gone, this Orange County-area district looks significantly more Democratic. After the district voted for Mitt Romney and John McCain, Hillary Clinton won by more than eight points in 2016.

California has a jungle primary system, in which the top two vote-getters in June, regardless of which party they represent, advance to the general election. There's a crowded field on the Democratic side, and the risk for Democrats is that they send someone too far to the left to the general election and lose this moderate seat.

9. Iowa's 1st District (Republican incumbent): Rep. Rod Blum's Northeastern Iowa district is perennially competitive because it encompasses one of Iowa's most Democratic cities, Dubuque. Blum, a conservative who doesn't quite match the district's politics, has been able to hang on in two elections that favored Republicans. But his job could be in jeopardy in a Democratic wave. State Rep. Abby Finkenauer appears to be the lead Democrat to challenge Blum.

8. Minnesota's 2nd District (Republican): Democrats are excited about a rematch between first-term GOP Rep. Jason Lewis and Democrat Angie Craig. Craig lost by two points in 2016 in this swing district spanning the south Twin Cities suburbs. But Democrats blame an independent candidate for eating into their win margin. This time around the race may hinge on what voters here, who went for Trump, think about the president now, given that Lewis has willingly cast himself in Trump's shadow.

7. Arizona's 2nd District (open): Democrats are hoping to flip this Tucson-area district now that GOP Rep. Martha McSally is running for Senate. Former Democratic congresswoman Ann Kirkpatrick, who represented another Arizona district and had a failed Senate bid in 2016, is running for the seat. But Republicans think she'll pay the price for jumping congressional districts.

6. Virginia's 10th District (Republican): Rep. Barbara Comstock has been one of Republicans' most vulnerable incumbents since she won this district in the outer D.C. suburbs in 2014. She disavowed Trump in 2016 on her way to reelection. But Democrats think even smart campaigning won't save Comstock in a region of the state that is rapidly turning blue. One of the more conservative counties in Comstock's district, Loudoun County, helped put a Democrat in the governor's mansion in 2017. There are at least four viable Democrats running to challenge her.

5. Minnesota's 8th District (open): Minnesota, in case you can't tell, is a battleground. This rural district is perhaps Republicans' top pickup opportunity in 2018, since Democratic Rep. Rick Nolan is retiring after three terms, shortly after Trump won his district by 15 points. Republicans think they have one of their best recruits of 2018 in St. Louis County Commissioner Pete Stauber, a former police officer from Duluth and member of a hockey dynasty.

4. Pennsylvania's 6th District (Republican): Pennsylvania is another battleground this November, thanks in part to the state's Supreme Court order for legislators to redraw all 18 congressional districts, which ended up favoring Democrats. That means GOP Rep. Ryan Costello's Republican-leaning district in the Philadelphia suburbs has now shifted among analysts to a toss-up. After watching Democrats dominate in the 18th District's special election, the Philadelphia Inquirer reports that Costello may see the writing on the wall and not run. If that's the case, this race will get even more competitive for Democrats without a GOP incumbent.

3. New Jersey's 2nd District (open): While you could make a case for any one of the seven races above to be swapped out with another equally competitive one, the next three races aren't nearly as contentious. Longtime GOP Rep. Frank A. LoBiondo's decision to retire suddenly makes this Atlantic City-area seat competitive for Democrats. His exit almost immediately elevated the Democratic front-runner, moderate state Sen. Jeff Van Drew. Republicans openly acknowledge they don't have a solid candidate to respond.

2. Florida's 27th District (open): Another GOP retirement all but forces the party to give up a congressional seat. Longtime Rep. Ileana Ros-Lehtinen announced she wouldn't be running for reelection, and with her departure goes perhaps the only Republican who can win this majority-Hispanic Southern Florida district that went for Clinton by 20 points.

1. Pennsylvania's 5th District (open): Our most likely seat to flip comes after the GOP congressman who had held it for eight years is retiring amid a sexual harassment scandal. But that's not the main reason this southwest Philadelphia-area district is the most likely to go to Democrats in November. In the new lines drawn by the Pennsylvania Supreme Court, perhaps no district got reshaped as drastically as GOP Rep. Patrick Meehan's, previously numbered Pennsylvania's 7th. While the old district narrowly went for Clinton by one point, Clinton would have won the new one by nearly 30 points. This is likely a Democratic giveaway now, and there's not much Republicans can do about it.