The ad blitz has worried some Democrats in swing districts who are being painted as do-nothing, pro-impeachment radicals. The Democrats have been urging party leaders for weeks to strike back with their own countermessage, to no avail.
Over the past month, GOP candidates have used anti-impeachment messages to try to recruit new supporters, and independent big-money groups boosting Republicans have launched roughly $10 million in ads aimed at Democrats in districts that President Donald Trump won in 2016.
Some of those vulnerable Democrats, who spoke on the condition of anonymity to speak candidly about private conversations, said that party leaders told them the cavalry is coming but shared no firm date.
House Majority Forward, a group with close ties to House Speaker Nancy Pelosi, D-Calif., launched a $1.5 million television ad campaign in support of some of them, but it lasted for just two weeks as the inquiry unfolded at the beginning of October.
The difference is especially stark on Facebook, where more than 100 congressional Republican incumbents and challengers and national pro-GOP groups ran anti-impeachment ads in the past month - roughly three times the number of such ads run on the Democratic side, according to an analysis by The Washington Post.
None of the 30 Democrats who are being targeted by national GOP groups ran Facebook ads in the past month to counter the attacks, The Post's analysis shows.
While some of the GOP ads ask for donations, the majority of them are designed to expand their base, asking people to "like" the Facebook page or fill out surveys on impeachment.
Such ads help gather data on people who agree with them and recruit new supporters who agree with their defense of the president in the impeachment inquiry.
"Just the term 'impeachment' invokes a visceral response," said Ben Goldey, spokesman for Rep. Paul A. Gosar, R-Ariz., who ran ads on Facebook asking his constituents to weigh in on impeachment. "It's been a useful strategy of connecting with our constituents."
The ads by Republican lawmakers often generated thousands of "impressions" - a measure of how many times users interacted with the ad - and sometimes for less than $100 per ad, data show.
Two official committees supporting Trump's reelection have run several thousand ads targeting Democratic leadership specifically and calling the impeachment a "scam" and a "hoax." The tone and language in these ads arebeing echoed by Republican members of Congress in their ads to constituents, data show.
Democratic strategists said they believe ads supporting or opposing impeachment have less impact on voters because they have already made up their minds on the issue.
Polls show that voters in general did not change their minds as a result of the hearings. Independents are divided on impeachment, and Trump's approval rating has hardly budged.
Democrats "are busy fighting for the priorities of the American people at the same time they ensure no one, not even the President of the United States, is above the rule of law," said Robyn Patterson, spokesperson for the Democratic Congressional Campaign Committee.
Other Democrats said ad spending by GOP groups varies by district and only a handful of markets are getting enough money to reach a significant audience.
"There's a strong correlation between cheap markets getting more ads and expensive markets getting fewer," said a Democratic strategist from a group tracking GOP ad spending, speaking on the condition of anonymity to share internal findings. "So this is less a strategic play and more geared to driving a national media narrative around the ad buys."
Still, some Democrats are getting impatient.
One Democrat was told to expect an ad blitz during the holidays touting the expected vote next week on a sweeping bill to lower prescription drug prices. But many of those representing GOP-leaning districts have pushed for faster help than that.
Other Democrats are counseling patience. Rep. Kurt Schrader, D-Ore., co-chairman of the moderate Blue Dog Coalition that counts several endangered freshmen in its ranks, acknowledged the skittishness but played down the need to punch back.
"We've had conversations as to, is this the right time to be punching back?" he said. "It's way early. Most people are not paying attention to this stuff."
Schrader said there would be plenty of time and money to counter the Republicans' message.
"Frankly, there's resources, you want to make sure you allocate them strategically at the right time," Schrader said. "We're trying to discuss whether or not it's time to put a little pushback or wait until summer or fall."
Meanwhile, GOP big-money groups are in lockstep with their anti-impeachment messaging, running ads where the Trump campaign or the national party are not and reflecting a similar tone and content as the president's campaign.
"This is a full-court press. We want to put as much pressure as we can on these representatives to make this vote as hard as it can be on them," said Kelly Sadler, spokeswoman for America First Policies, the main pro-Trump politically active nonprofit.
They are mirroring the president's message to stay targeted on "the sham of the process, partisanship and do-nothing Democrats," Sadler said.
America First Policies this week launched $2.3 million in advertisements and separately ran a $1 million ad campaign when the impeachment inquiry began. The group is targeting vulnerable Democrats in 27 House districts on television, Facebook, texts and full-page local newspaper ads.
American Action Network, the main politically active nonprofit supporting House Republicans, has launched a $7 million television and digital advocacy campaign aimed at 37 key congressional districts.
The group polled viewers in three of those districts as the ads rolled out and found that constituents were quoting the messages of the ads verbatim - indicating to officials that their message is resonating, according to the group's polling memo.
"The data shows that it's what folks back home actually believe about this whole process," said Dan Conston, president of American Action Network.
Among the few Democrats running pro-impeachment Facebook ads are state office candidates, who are finding that they can garner attention by nationalizing their campaigns and tying it to the impeachment inquiry.
"I STAND for impeaching the President in order to restore American values and end this nightmare," reads a Facebook ad by the campaign of Anton Andrew, a Democrat running for the Pennsylvania state House in a southeastern district.
In an interview, Andrew said he is increasingly hearing about impeachment as a major issue for his district's constituents: "It's sort of irresponsible and wishful of me to think that what's going on in Washington isn't going to affect my race."
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