By Simone Pathe, CNN

(CNN) -- The national environment has worsened so much for President Donald Trump that Democrats are now competing in once-red House districts, while Republicans are trying to stem their losses.

Seven of the 10 seats on CNN's ranking of districts most likely to flip partisan control are now held by Republicans -- one more than two weeks ago, which reflects the degree to which the battlefield has shifted in Democrats' favor. The rankings are based on CNN's reporting, as well as polling, fundraising and advertising spending data.

It's hard to underscore how remarkable the shift in the landscape is. After Democrats' historic gains in the 2018 midterms, Republicans thought they'd be on the offensive in 2020, blazing a trail back to the majority by targeting the 30 districts Trump won in 2016 that are held by Democrats. But the President is now proving to be a roadblock even in many of those districts, while helping Democrats open up new avenues to expand their majority in once-red districts.

Inside Elections with Nathan L. Gonzales, a CNN contributor, shifted 20 House races toward Democrats last week -- and just three toward Republicans. It's no longer a question of whether Democrats will pick up seats and grow their majority, it's by how much. Inside Elections now projects Democrats will post a net gain of 10 to 20 seats.

Trump won nearly all of the GOP-held districts on CNN's ranking of seats most likely to flip. But he's not coming close to his 2016 margins or is on track to lose many of these districts, putting down-ballot Republican candidates in a difficult spot.

Several Democratic-held seats that Trump won drop off the list. Oklahoma's 5th District and Utah's 4th District, for example, are still tough seats for Democrats to hold, but they've been replaced by suburban seats in Republican areas that look especially competitive given Trump's sagging numbers. In fact, there are still other Democratic pick-up opportunities, like Texas' 24th District, New York's 24th District or California's 25th District, that may deserve their own spots on this list. But the difficulty of choosing which to put on a top 10 list only underscores how good things look for Democrats compared to Republicans right now.

Two weeks out from Election Day, here are the seats most likely to flip:

1. Georgia's 7th District

Home to the closest race in the country in 2018, this suburban Atlanta district is an open seat this year. Republicans were hoping that might actually improve their chances of holding the seat, given that current GOP Rep. Rob Woodall -- who won by about 400 votes in a recount -- wasn't much of a campaigner. But fresh off her narrow loss, Democrat Carolyn Bourdeaux is running again, benefiting from a favorable national environment in a diversifying district that's soured on Trump despite backing him four years ago. Republicans are using their law-and-order messaging against Bourdeaux, while Democrats are arguing that Republican Richard McCormick, who's backed by the House Freedom Caucus' political arm, is too extreme for the district and trying to tie him to Trump. Bourdeaux has outraised McCormick and is also likely to get a boost from Democrats investing in this demographically changing state at the presidential level and in two Senate races.

2. Nebraska's 2nd District

Trump narrowly carried this district in 2016, and with it, picked up an electoral vote. But the tide has turned against him in the Omaha suburbs, which is imperiling Republican Rep. Don Bacon. The sophomore Republican is locked in a rematch with Democrat Kara Eastman, whom he defeated by just a couple points in 2018. Eastman recently earned the endorsement of former Democratic Rep. Brad Ashford (whom Bacon defeated in 2016 and whose wife Eastman defeated in the primary this year). And Republicans have been trying to paint Eastman, who supports "Medicare for All," as "an extremist." But Eastman has been trotting out Republican endorsements in TV ads, and Democrats say she's being much smarter about the way she communicates her health care message this year. Joe Biden's endorsement should also mitigate some of the attacks on her for being too far to his left -- and help her ride his coattails.

3. Texas' 23rd District

This open seat, which has consistently been No. 1 on the list, slides down a few places because the dismal environment for Republicans nationally hasn't trickled down to this rural border-district as much as in other places. Having run two years ago, Democrat Gina Ortiz Jones, an Air Force veteran, got a head start on Republican Tony Gonzales, who emerged from a late GOP primary with little cash. But his profile as a Hispanic Navy veteran also resonates here. Still, with GOP Rep. Will Hurd retiring, Democrats have a good shot of picking up the open seat, which is one of just four Clinton districts still held by a Republican.

4. New Mexico's 2nd District

While many Democrats in Trump districts are looking at improving fortunes, freshman Rep. Xochitl Torres Small is still locked in a competitive rematch with Republican Yvette Herrell in a district the President won by about 10 points. This rural district doesn't fit the profile of many of the other seats Democrats flipped in 2018, and the President will likely carry the district again.

5. Indiana's 5th District

Trump won this district by nearly 12 points in 2016, but the suburbs north of Indianapolis are no longer a fan of the President. With GOP Rep. Susan Brooks not running for reelection, it's an open seat that has become a top Democratic pick-up opportunity after not even having been on the map two years ago. It's the kind of well-educated area that typifies the partisan shift happening around geographic lines in this country. Democrat Christina Hale has outraised the Club-for-Growth-backed Victoria Spartz, even including the Republican's self-funding, and is likely to benefit from a favorable national environment.

6. New Jersey's 2nd District

Democrats won this seat in the 2018 midterms, but then Rep. Jeff Van Drew switched parties and cozied up to the President. That may have looked like a safe strategy for a South Jersey district that Trump carried by about 5 points. But times have changed. Public polling has given Biden a slight edge here, with nearly half of voters saying they're bothered by the congressman's party switch. Democrat Amy Kennedy is leaning into that message, hitting Van Drew in a recent ad by saying she'll "never trade her South Jersey values to benefit myself." The wife of former Rhode Island Rep. Patrick Kennedy was at 49% to Van Drew's 44% among registered voters in Monmouth University's early October survey. That's within the margin of error. But it doesn't look like Van Drew's getting much outside help to put him over the top.

7. Ohio's 1st District

This is another increasingly suburban seat where Republicans are worried about the fundamentals of the district moving away from them, not to mention an incumbent who's not keeping pace with his challenger's fundraising. Democrat Kate Schroder outraised GOP Rep. Steve Chabot by a million dollars in the third quarter. Chabot prevailed by about 4 points against a flawed challenger in 2018, but now he's the one being dogged by headlines and attack ads about campaign finance issues. And there's precedent for him losing. With Biden competitive in the Buckeye State, and especially this district, there's reason to think the environment could drag Chabot down, just as it did in 2008, when he lost.

8. Minnesota's 7 District

There's no district currently represented by a Democrat where Trump did better in 2016. The President carried this sprawling agricultural seat by 31 points, and at the same time, Democratic Rep. Collin Peterson won reelection. He won again in 2018, becoming the chairman of the Agriculture Committee. Peterson's no average Democrat -- he voted against impeachment and opposes abortion rights. But with down-ballot races becoming more nationalized and ticket-splitting less common, there may be only so long he can hold on. Unlike the past two cycles, he's facing a Republican who's raising money and has national party backing. Former Lt. Gov. Michelle Fischbach and her allies are trying to tie the incumbent Democrat to House Speaker Nancy Pelosi, while Democrats are attacking her for calling Obamacare a "disaster," which, interestingly enough, is a law Peterson voted against in 2010 -- although he's opposed subsequent efforts to repeal it.

9. Arizona's 6th District

This district outside of Phoenix makes the list for the first time, but it's become increasingly competitive over the past few months both because of the wealthy suburbs that don't like the President and because of problems the incumbent brought upon himself. GOP Rep. David Schweikert admitted to 11 ethics violations, earning him an official reprimand from the House this summer. He's facing emergency room doctor Hiral Tipirneni, who's outraised him and should benefit from Biden and Democratic Senate candidate Mark Kelly's strength in the district, which has one of the highest rates of college education of any still represented by a Republican, according to Inside Elections.

10. New York's 11th District

Freshman Rep. Max Rose flipped this Staten Island district in 2018, and even if the President's numbers are worse across the country, he still has a base in the 11th District, which he carried by about 10 points. Republicans insist their spending here has moved the race in Republican Nicole Malliotakis' direction, and even Democrats admit that this district, which is home to police and other first responders, is one place where the GOP's law-and-order attacks have some resonance. But they see Rose, an Army veteran who's running ads saying he opposes defunding the police and calling Democratic Mayor Bill de Blasio "the worst mayor in the history of New York City," as the perfect candidate to deflect those attacks. And Democrats ultimately feel confident that their significant spending advantage in the final weeks of the race will make a difference.