Washington CNN  — 

While Democrats came up short in last Tuesday’s Arizona special election – losing by fewer than five points in a district Donald Trump carried by 21 points – the results offer yet another sign the party still holds the energy edge heading into November’s midterm election.

As we approach a cluttered stretch of the primary calendar, the results from those contests – and the next wave of campaign fundraising reports in June – will help to clarify the Democratic Party’s prospects this fall.

That deadline will offer a good idea of whether Democrats can maintain momentum. More than three dozen Democratic House candidates outraised Republican incumbents for the second quarter in a row after the most recent filing.

Trump’s national approval rating, meanwhile, continues to hover around 40%, which poses an additional challenge for GOP candidates running this year.

With all that in mind, we are moving a dozen Republican held House districts to a more competitive rating. Each race below is moving in the direction of the Democrats even though the Republican remains favored in all of them.

As a reminder, Democrats need a net gain of 23 seats in order to win control of the House. Of the 11 races rated Lean Democratic by CNN, seven are currently held by Republicans, as are 19 of the 21 races rated Toss-Up. Of the 25 races CNN now rates as Lean Republican, all are Republican-held – or in the case of the Ohio 12th District seat vacated by Pat Tiberi, had been held by a Republican.

AZ-06: You might not have to look very far for reverberations from last week’s special election results. The neighboring 6th District, represented by GOP Rep. Dave Schweikert, is more favorable terrain for Democrats than the 8th District – more suburban and home to a higher percentage of college graduates. Trump won here by 10 points, a much slimmer margin than Mitt Romney’s 21-point spread in 2012. Arizona has a late primary at the end of August, but Democrats believe Arizona State University nursing professor Heather Ross has the potential to make this race more competitive if she emerges as the nominee. Race moves from Solid Republican to Likely Republican.

AR-02: Arkansas state Rep. Clarke Tucker gives Democrats a candidate who could make inroads in the 2nd District, home to Little Rock. Tucker announced his bid in early February, and despite the late start managed to beat GOP Rep. French Hill in fundraising by about $130,000 in the first quarter. Trump won the district by 10 points, slipping from Romney’s 12-point margin four years earlier. Race moves from Likely Republican to Lean Republican.

CA-04: There are some shared qualities with the northern Sacramento suburbs of California’s 4th District and the Phoenix suburbs from Arizona’s 8th District. Both have a large contingent of senior citizens. They also have a similar racial breakdown. Trump won only 53% in this district, falling off five points from Romney’s 58% mark in 2012. Veteran GOP Rep. Tom McClintock has been outraised by leading Democratic candidate Jessica Morse in three consecutive fundraising quarters. Morse also has a $715,000 to $676,000 cash on hand lead. Race moves from Solid Republican to Likely Republican.

FL-16: GOP Rep. Vern Buchanan has won comfortably the last two cycles, and while he remains a heavy favorite he’ll have to work a bit to earn a seventh term in this Sarasota-area district. He’s sitting on $2.5 million in the bank and raised $480,000 in the first quarter. He’ll likely face Sarasota attorney David Shapiro in November. The Democrat raised $400,000 in the first quarter and is just shy of half a million cash on hand. Race moves from Solid Republican to Likely Republican.

IL-14: Lauren Underwood, a registered nurse and former Department of Health and Human Services adviser in the Obama administration, scored 57% of the vote in a crowded Democratic primary last month. Democrats are hopeful she can give GOP Rep. Randy Hultgren a serious challenge in the 14th District, which is made up of Chicago exurbs. Hultgren has benefited from weakly-funded challengers in previous cycles – a luxury he likely won’t have against Underwood, who raised $465,000 in the first quarter. Hultgren brought in $360,000 – but still has a significant cash on hand advantage ($783,000 vs. $235,000). While Trump won this district by four points in 2016, Barack Obama carried it with 50% in 2008. Race moves from Likely Republican to Lean Republican.

MI-01: This northern Michigan district, which includes the Upper Peninsula, went for Trump by 22 points, but gave Romney and McCain single-digit victories. The race is shaping up to be a contest between two Marine Corps veterans – incumbent GOP Rep. Jack Bergman and Democratic candidate Matthew Morgan. Morgan has outraised Bergman in each of the past two quarters and now holds a $317,000 to $307,000 advantage in terms of cash on hand. Race moves from Solid Republican to Likely Republican.

NJ-03: GOP Rep. Tom MacArthur’s support for Trump’s agenda (health care repeal and tax cuts) and a strong challenge from likely Democratic nominee Andy Kim make this swing district competitive. The district went for Trump by six points, but backed Barack Obama by four in 2012. Kim, a former national security adviser to Obama, outraised MacArthur by more than $200,000 in the first quarter, though the Republican still holds an advantage of roughly $270,000 in cash on hand. Race moves from Likely Republican to Lean Republican.

NM-02: Both parties are facing primary fights in the 2nd District, which opened up when GOP Rep. Steve Pearce decided to run for governor in the Land of Enchantment. On the Republican side, it appears to be a contest between state Rep. Yvette Herrell and former Hobbs Mayor Monty Newman. Xochitl Torres Small looks to the the frontrunner for the Democratic nod. The attorney and former field representative for Sen. Tom Udall raised $313,000 in the first quarter, beating Newman and Herrell combined. While registered Democrats outnumber Republicans in this district, Trump carried it by 10 points, which was a wider margin than Romney’s seven-point win in 2012. Race moves from Likely Republican to Lean Republican.

OH-01: All eyes in Ohio are on the 12th District special election in August, but the House race in the Buckeye State to watch in November is likely to be the 1st District, where GOP Rep. Steve Chabot could face a serious challenge from Democrat Aftab Pureval. Pureval, the Hamilton County Clerk of Courts, outraised Chabot by nearly half a million dollars in the first quarter of 2018. This district, which includes the western and northern parts of the Cincinnati metro area, went for Trump by seven points and Romney by six points. Race moves from Likely Republican to Lean Republican.

OH-07: Speaking of Ohio, GOP Rep. Bob Gibbs improved a bit on his lackluster $86,000 fundraising quarter at the end of 2017 – raising $113,000 in the first quarter of 2018. Democrat Ken Harbaugh, a former Navy pilot, hauled in $441,000 – after raising $272,000 in the fourth quarter of 2017. Gibbs still has $1.3 million in the bank compared to Harbaugh’s $726,000. The Gibbs campaign and Ohio Republicans have been attacking Harbaugh’s primary opponent, Patrick Pikus, who is little known and has only raised $5,000 for his campaign – perhaps in an attempt to raise his name ID. Democrats see the move as an indication the Gibbs campaign views Harbaugh as a threat. Race moves from Solid Republican to Likely Republican.

WA-05: Rep. Cathy McMorris Rodgers, a member of the House GOP leadership, has a tough race on her hands against Democrat Lisa Brown, the former chancellor of Washington State University Spokane. A recent poll of the district showed McMorris Rodgers leading Brown by six points, 44% to 38%, with 16% undecided. McMorris Rodgers hauled in $776,000 in the first quarter compared to $649,000 for Brown – and the Republican leads in cash on hand by more than $700,000. Race moves from Likely Republican to Lean Republican.

WI-06: Even with House Speaker Paul Ryan’s retirement, a lot of attention in the Badger State will be paid to the 1st District race. But the contest in the 6th District could be the best pickup opportunity in the state for Democrats, with Dan Kohl – nephew of former Sen. Herb Kohl – giving the party a serious challenger to GOP Rep. Glenn Grothman. Kohl has outraised Grothman now in three consecutive quarters and has $136,000 more in the bank to start April. This is another district where Trump outperformed previous Republican candidates, winning by 17 points. Romney won it by seven in 2012 while Obama carried the district in 2008. Race moves from Likely Republican to Lean Republican.

Correction: This story has been updated to reflect the correct first quarter fundraising numbers for the candidates running in Illinois' 14th District.

Adam Levy, Eric Bradner and Keating Holland contributed to this report