The fundraising email from California Democratic Sen. Kamala Harris hit inboxes Tuesday evening with the subject line “Proud to announce.” But it wasn’t about Harris making history as her party’s vice presidential nominee.

“I’m excited to let you know … that I’m proudly endorsing Cindy Axne for Congress!” read the email, touting the Iowa Democrat who is in a hotly contested reelection race in the Des Moines-based 3rd District.

Axne’s fundraising blast epitomized how Democrats in competitive House and Senate races could tap into the energy surrounding former Vice President Joe Biden’s decision to choose Harris as his running mate. The announcement appeared to be a fundraising boon for Democrats on Tuesday, with $10.8 million flowing through the ActBlue platform, according to The New York Times. The Democratic Senatorial Campaign Committee also had its best online fundraising day ever.

Biden campaign spokesman Matt Hill said in a statement to CQ Roll Call that Biden has been building a coalition “to not only beat Donald Trump, but to elect Democrats up and down the ballot.“

Harris, he said, “lifts up women of color across the country, and supercharges the path to victory for our campaign and Democrats running everywhere.”

But Harris has taken positions that were more liberal than Biden has, and that could be problematic for Democratic incumbents in the 30 districts President Donald Trump carried in 2016 and Senate candidates hoping to flip states Trump won.

Republicans wasted no time trying to tie vulnerable Democrats to Harris’ positions on issues such as the Green New Deal, which would overhaul the economy to combat climate change. Harris co-sponsors the Green New Deal resolution in the Senate, as well as Vermont Sen. Bernie Sanders’ “Medicare for All” legislation. But Harris did introduce her own health care plan during her presidential campaign that would build on Medicare and still allow for private insurance coverage.

“Doug Jones has a Kamala Harris problem,” read an email from the National Republican Senatorial Committee on Wednesday, referring to the most vulnerable senator running for reelection this year. The Alabama Democrat is seeking a full term in a state Trump carried by 28 points.

“Despite his claims of bipartisanship, anti-Trump Democrat Doug Jones has hitched his wagon to a potential Biden-Harris administration,” said NRSC spokeswoman Paige Lindgren. She said Jones “has given up on representing the conservative values that Alabamians hold true.”

Republicans working in House races also sought to link vulnerable Democrats to the top of the ticket after Biden’s announcement. Calvin Moore, a spokesman for the GOP super PAC Congressional Leadership Fund, said in a Tuesday statement that “House Democrats will have a difficult time keeping up their phony moderate charades.”

California Democratic Rep. Ami Bera said he was not concerned about GOP attacks tying Democrats to some of Harris’ liberal positions.

“It’s the same old Republican playbook where they can’t really run on President Trump’s failed record of leadership and his mishandling of the pandemic. So they’re going to try to create other diversions,” said Bera, who co-chairs the Democratic Congressional Campaign Committee’s Frontline program for vulnerable members.

Down-ballot boost?

Some Democratic strategists said Wednesday that they don’t believe Harris will be a drag on down-ballot candidates. They argued instead that her position as the first Black and Asian woman to be a major party’s vice presidential nominee would motivate Democratic voters.

“Senator Harris on the ticket is a great benefit for women down the ballot, especially women of color,” Democratic strategist Achim Bergmann wrote in an email. “Her candidacy will help reinforce their own credentials for voters. And the ticket will mobilize Democrats to vote.”

Jones, who made his reputation as a prosecutor who decades later won convictions for the 1963 Birmingham church bombing that killed four young Black girls, captured the seat in 2017 in part because of an aggressive effort to turn out Black voters. Harris at the top of the ticket could provide further motivation for supporters of Jones and others.

“She’s a history-making candidate who will help energize Black voter turnout in a way that boosts down-ballot Democrats in key Senate battlegrounds from North Carolina and Georgia to Michigan and Alabama,” one Democratic consultant said. “Strong participation from Black voters and holding our own with independents are the path to victory in these states.”

Democrat Sri Kulkarni’s campaign manager, Allen Chen, said Tuesday night that Harris’ nomination could help Kulkarni flip Texas’ 22nd District, a growing and diversifying district in the Houston suburbs.

“With Senator Harris and Sri Kulkarni on the ticket, TX-22 will see a historic number of South Asian voters heading to the polls,” Chen said in an email.

Democratic Congressional Campaign Committee spokesman Darwin Pham suggested Harris could further mobilize Asian American and Pacific Islander voters in competitive House races, particularly in suburban districts in California, Texas and Georgia.

“Having Kamala Harris on the ticket as VP makes clear that all of our communities can have a seat at the highest table in the land, and a pivotal role in charting its future,” Pham said. “The AAPI community is energized, and we are going to continue doing the work to turn out every one of these voters to protect and expand our majority.”

Harris has not shied away from weighing in on House and Senate races since the vice presidential vetting process got underway.

Since unveiling a slate of down-ballot endorsements in May, Harris has backed even more congressional candidates, including Hiral Tipirneni, who’s running against scandal-plagued GOP Rep. David Schweikert in Arizona’s 6th District. Tipirneni touted Harris’ backing on Twitter as a “HUGE ENDORSEMENT,” a sign Harris is seen as an asset even in a district Trump won by 10 points.

Last week, Harris sent a flurry of tweets encouraging her followers to donate to congressional candidates in competitive races, largely highlighting candidates of color, including Jackie Gordon in New York’s 2nd District and Candace Valenzuela, who would be the first Black and Latina woman in Congress, in Texas’ 24th District. Harris has also hosted fundraisers for Democratic Senate candidates, including Montana Gov. Steve Bullock, Maine House Speaker Sara Gideon and South Carolina Democrat Jaime Harrison, according to CBS.

Ian Russell, a Democratic consultant and former DCCC political director, wrote in an email that Harris’ House endorsements are “another proof-point of what a team player she is.”

“She doesn’t bring new baggage that down-ballot candidates could trip up having to answer for, and she’ll add energy to an already fired-up and united Democratic Party,” Russell wrote.