House Democrats seeking reelection Tuesday started the 2020 cycle on defense, with 30 members running in districts President Donald Trump won in 2016. Republicans believed the decision by a near-unanimous Democratic Caucus to impeach Trump would seal their fates. But that historic vote has been overshadowed by the coronavirus pandemic and resulting economic downturn. 

As Trump’s support in public polls sagged and Democrats continued to post eye-popping fundraising numbers, Republicans saw their path to the House majority narrow. Republicans need a net gain of 17 seats to win control of the chamber, but some GOP strategists acknowledge it’s more likely that Democrats grow their majority.  

Control of the Senate has been less predictable, with several very close races heading into Election Day. Democrats need a net gain of three or four seats, depending on which party wins the presidency, because the vice president breaks ties in the Senate. 

The number of competitive Senate races has expanded throughout the cycle, thanks in part to close presidential margins in battleground states and blockbuster Democratic fundraising. Inside Elections with Nathan L. Gonzales rates 14 Senate races as competitive — two seats held by Democrats and 12 by Republicans. 

Here are the dynamics that defined the battle for Congress in 2020: 

Top of the ticket 

The race for the White House has loomed large on congressional races. GOP candidates may have been at least as upset as his own supporters that Vermont Sen. Bernie Sanders, an independent who identifies as a democratic socialist, didn’t win the Democratic nod for president. Even with the more mainstream former Vice President Joe Biden at the top of the ticket, down-ballot Republicans have tried to run against socialism. But Biden has come out against progressive proposals, such as the call to defund the police. 

In reality, Trump was a drag on many congressional candidates. Longtime Maine GOP Sen. Susan Collins has struggled to maintain her independent brand during the polarization of the Trump era, and she’s among her chamber’s most vulnerable.

[10 most vulnerable senators: Outspent Republicans overrun final list before election]

The first presidential debate was something of a disaster for GOP candidates, followed shortly by Trump’s COVID-19 diagnosis. Trump and Republicans mounted a comeback, but it’s not clear whether the president has sufficiently rebounded, especially in the suburbs, to help some of the most endangered GOP nominees down ballot. 

Coronavirus pandemic 

Whether it was concerns about health matters or the economy, the pandemic has been the most important issue to voters since shutdowns began in mid-March, campaign strategists in both parties say. 

With unemployment spiking, Trump and down-ballot Republicans lost the ability to campaign on a strong economy, and many shifted to warning that a Biden win would keep businesses from reopening. For Democrats, the crisis underscored their persistent focus on health care and allowed some to blame Trump’s handling of the crisis for the more than 230,000 deaths nationwide. 

The pandemic also upended how candidates connected with voters, with many opting to limit in-person events and devote more resources to phone banking and digital organizing.   

Fundraising 

The fundraising hauls of Democratic candidates, particularly Senate challengers, have blown away even veteran political operatives. The record-holder for the biggest fundraising quarter is Jaime Harrison, whose campaign collected nearly $58 million in donations from July through September, putting the GOP stronghold of South Carolina in play. 

The death of Supreme Court Justice Ruth Bader Ginsburg led to a surge of Democratic donations, and every Republican senator facing a competitive race was outraised in the third quarter, according to a CQ Roll Call analysis. The average Democratic challenger in 11 races rated competitive by Inside Elections raked in $23.1 million from July through September. That’s more than twice the $10.4 million average for their incumbent Republican opponents.

House Democrats, including the party’s most vulnerable members, also built strong fundraising advantages over their GOP counterparts. Anti-Trump sentiment has fueled much of the donating, especially from small-dollar donors. 

All the Democratic cash sent the GOP’s big donors dashing off mega-checks to super PACs and other outside groups, which have also blown through their previous spending records.

Retirements 

House Democrats are eyeing pickup opportunities in seats where Republicans opted to retire. Those include Georgia’s 7th District, which Rep. Rob Woodall is vacating after winning the closest House race of 2018, and Indiana’s 5th District, where Rep. Susan W. Brooks is retiring. A slew of Republican retirements in Texas, which Democrats nicknamed the “Texodus,” opened up competitive seats in the Dallas and Houston suburbs.

Republicans are hoping to flip Iowa’s 2nd District since Democratic Rep. Dave Loebsack is retiring. But Democrats are confident that former state Sen. Rita Hart can defeat state Sen. Mariannette Miller-Meeks, who unsuccessfully challenged Loebsack three times.

There’s also a competitive race for an open Senate seat, thanks to Kansas Republican Pat Roberts’ decision to retire. Democrats haven’t won a Senate contest in Kansas since 1932, but state Sen. Barbara Bollier has had a sizable financial advantage in her race against GOP Rep. Roger Marshall.  

Mixed messages 

Democrats reused the party’s successful 2018 playbook when candidates running on pledges to support health care and curb corruption helped win control of the House. For Senate GOP candidates — such as Iowa’s Joni Ernst, who won in 2014 by attacking the 2010 health care overhaul — it reflected just how much the public has shifted on the law known as Obamacare.  

Republicans, meanwhile, have focused on job growth and helping the economy to recover from the COVID-19 crisis. They’ve also warned of a radical-leftist agenda and have linked vulnerable Democrats, such as New York Rep. Max Rose, to calls by progressives to defund police departments (something Rose said he does not support). 

Reruns: A cycle of do-overs 

Call it a re-cycle, perhaps. It’s been a cycle of rematches, particularly in some of the tightest House races. Repeat candidates, undeterred by losing in 2018, came back for another try, and many face decent odds of morphing from losers to members-elect. 

Take Kara Eastman, the Democratic challenger to GOP Rep. Don Bacon in Nebraska’s 2nd District. Eastman lost to Bacon by about 5,000 votes in 2018 and is banking on a boost from Biden voters this year to carry her to victory. Bacon is now CQ Roll Call’s most vulnerable incumbent House member. 

[As campaign ends, GOP dominates list of 10 most vulnerable in the House]

And Republican Yvette Herrell has a good shot at unseating Rep. Xochitl Torres Small in New Mexico’s 2nd District, after narrowly losing to the Democrat in 2018. Four former GOP House members are also running for their old seats, including California’s David Valadao, who lost an extremely close race two years ago.