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Key House races to watch in 2018
01:54 - Source: CNN
Washington CNN  — 

Congressional Democrats, benefiting from President Donald Trump’s low approval ratings and historic trends working against the party in power, sit in the catbird seat in the battle for control, according to new House and Senate ratings from CNN.

The House, in which Democrats need a 24-seat pickup to win the majority they lost in 2010, looks more favorable at the moment – largely due to the wide number of GOP-held seats in some level of jeopardy.

Related: CNN’s Key Races - House

CNN’s Key Races - Senate

According to CNN ratings, 61 Republican seats are either toss-ups (15), leaning GOP (21) or likely GOP (25). Compare that to just 22 Democratic seats in any sort of jeopardy this fall and you begin to grasp the depth of Republican vulnerability.

There are two major reasons why so many Republican seats are in danger this fall:

1. The 2010 and 2014 midterms were massive seat windfalls for Republicans. They won House control in 2010 and added to it in 2014. Following the 2014 midterms, Republicans had their largest House majority since 1929. What that means is the only place for them to go is down in terms of the seats they control.

2. Retirements in hard-to-hold districts have ravaged Republicans this year. Already 35 House GOPers have announced plans to retire or run for other offices this fall, far ahead of historic patterns. And it’s not just the number of retirements that is hurting Republicans – it’s where the seats are. Already six of the 23 Republicans in districts Hillary Clinton won in 2016 are leaving and several others – including New Jersey Rep. Rodney Frelinghuysen, who announced his retirement Monday – are walking away from seats where Trump barely won in 2016.

The unevenness of the playing field is no guarantee for Democrats, of course. Political winds can – and do – shift and the vast majority of Republican incumbents have been aware for the better part of the last year that they would face tougher-than-normal reelection races.

Plus, netting 24 seats is no easy task. Consider this: Even if Democrats win every one of the seats Clinton carried in 2016 that are currently held by a Democrat – and they won’t – the party would still be a single seat short of the majority.

Still. Democrats have experienced a candidate recruitment windfall thanks to historic trends (the president’s party has lost an average of 25 House seats in a first-term, midterm election in the post World War II era) and a current political environment dominated by Trump’s unpopularity.

Combine that glut of quality candidates with a widening playing field and the weight of history and Democrats look to be in very strong position to win back control of the House – with the important caveat that the election is still 280 days away.

On the Senate side, things look less rosy for Democrats – but still far better than the party had any reason to expect when this election cycle started a year-plus ago.

The raw numbers are daunting for Democrats. They are defending 26 seats this November as compared to just 8 for Republicans. Of those 26 seats, 10 are in states that Trump carried in 2016 – including five (Indiana, Missouri, Montana, North Dakota, West Virginia) that he carried by double digits.

Given the Republican tilt of the playing field, some GOPers were talking about the possibility of controlling a filibuster-proof 60 seats after the 2018 election. No one is talking that way now.

The stunning victory by Democratic Sen. Doug Jones in Alabama was not only a sign of how enthusiastic the Democratic base is but also narrowed the GOP Senate majority to just two seats.

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Key races to watch in the Senate in 2018
02:16 - Source: CNN

The political environment – and the ongoing battle between the establishment and Trump wings of the GOP – have also contributed to faltering Republican prospects.

In Montana and North Dakota, Republicans have struggled to land a top-tier recruit despite the clear GOP tilt of those two states. Republicans have the opposite problem in West Virginia and Indiana, where contested – and costly – primaries are on the horizon.

In fact, of the five states Trump won by double digits in 2016, only in Missouri, where Democratic Sen. Claire McCaskill is running for re-election, did Republicans get the candidate they wanted with a relatively clear primary field.

With just eight total Republican seats on the ballot this fall, Democratic pick-up opportunities are far more limited. But they do have two: Arizona and Nevada.

The Arizona open seat, caused by the retirement of prominent Trump critic Sen. Jeff Flake, sets up a contested and ideological primary on the Republican side while Rep. Kyrsten Sinema has a more straightforward path to the Democratic nomination. In Nevada, Sen. Dean Heller faces a primary from perennial loser Danny Tarkanian and a likely general election faceoff against Democratic Rep. Jacky Rosen.

The disparity of seats being defended by the two sides gives Senate Republicans a considerable, foundational edge. But that edge has eroded over the past year as Trump’s unpopularity has come home to roost – in both polling and candidate recruitment in individual races.

Republicans are still the safe bet to hold the Senate, but a path now exists for Democrats to get back the majority – albeit a very narrow path.

Taken together, Democrats are well-positioned to make significant gains in the House and hold their losses in the Senate down in 2018, according to CNN’s ratings. The question now is whether Trump can find a way to effectively rally the Republican base and move his job approval numbers from the high 30s into the mid 40s (or even higher) between now and Election Day.

Count me as skeptical given the divisions in the country and the way in which Trump has governed over his first year in office.

CNN’s Terence Burlij, Eric Bradner, Wade Payson-Denney and Adam Levy contributed reportings; Visualizations by Joyce Tseng