Washington (CNN) President Donald Trump's new Willie Horton-style web video posted to Twitter on Wednesday night represented a new flashpoint in a culture war he is stoking ahead of next week's midterm elections. But it also came as part of a broader strategy GOP candidates are using in key House, Senate and governor's races.

Republican candidates and outside groups involved in tough races, particularly in deep-red states and districts where turning out the conservative base is all that matters, are airing television advertisements stoking fears and spreading misinformation about the group of migrants still 900 miles from the Southern border.

It's the GOP's closing argument in Tennessee, where Republican Rep. Marsha Blackburn, who faces Democratic former governor Phil Bredesen in a competitive Senate race, has aired ads that mention the "caravan" nearly 800 times, according to an analysis by Kantar/CMAG, which tracks political ads.

One Blackburn ad describes the migrants as "gang members, known criminals, people from the Middle East, possibly even terrorists." A narrator says that "Marsha Blackburn will stand with Trump to build the wall and stop the caravan."

The migrants, traveling as a group for safety, have left their home countries and are heading to the United States. Trump and his allies have tried to stoke fears about the group and tie them to Democrats ahead of the midterm elections. There have been no reports, in the press or publicly from intelligence agencies, to suggest there are people from the Middle East embedded in the caravan.

The Senate Leadership Fund, a super PAC aligned with Senate Majority Leader Mitch McConnell, has also aired ads attacking Bredesen. "The caravan is coming, yet Bredesen is too liberal to care," a narrator says in one ad.

The ads mimic a strategy Trump set into motion weeks ago. Ignoring some Republicans' pleas to put a booming economy at the forefront in the midterms, the President has launched an all-out culture war depicting immigrants, particularly Latinos, as a threat to the nation. He said Wednesday he might send 15,000 troops -- three times the number currently fighting ISIS in Iraq -- to meet the group of migrants. He has hyped it as an imminent threat, even though the group is shrinking in numbers and still weeks from the border.

On Wednesday night, Trump escalated his race-fueled campaign further, posting on Twitter a video produced by the Republican consulting firm Jamestown Associates that depicts Democrats as plotting to help people they depict as Central American invaders overrun the nation with cop killers.

The web ad features Luis Bracamontes, a Mexican man who had previously been deported but returned to the United States and was convicted in February in the killing of two California deputies.

"I'm going to kill more cops soon," Bracamontes is shown saying in court as captions flash across the screen reading, "Democrats let him into our country. Democrats let him stay."

The web ad recalled the 1988 "Willie Horton" ad backed by supporters of George H.W. Bush's presidential campaign. It depicted Democratic opponent Michael Dukakis as responsible for the rape Horton, a convicted murderer, committed while out of prison while furloughed under a Massachusetts program. The ad was seen as playing into white fear and racist stereotypes of African-American.

Thirty years later, Trump's spot is the Willie Horton ad on steroids -- and playing into the same racist stereotypes, this time with Latino immigrants.

A source close to the White House described the web ad as well as Trump's immigration push as "changing the argument from family unification to invasion."

"It's clearly working. We are all talking about it and not health care," the source added.

New CNN polls underscore why Republicans -- who widely view maintaining control of the House as a long-shot but see turning out conservatives in key Senate races as an opportunity to expand their majority there -- are all-in on a strategy of fear-mongering over racial divides.

In Arizona, 50% of Republican likely voters say immigration is the most important issue -- up from 35% in September. And in Nevada, 42% of Republican likely voters identified immigration as the most important issue, an increase from 28% in September. Both states feature competitive Senate races.

What's not clear: Whether Republican voters' shifting views are a response to Trump's messaging, or whether Trump and other GOP candidates are shifting their messaging as a reaction to the movement in their base.

Some Republicans running in more moderate territory have broken with Trump over his fear mongering on immigration. Rep. Carlos Curbelo, a Florida Republican running for re-election in a district Hillary Clinton won in 2016, called the new web ad "part of a divide-and-conquer strategy."

"I hope this doesn't work. I hope that type of strategy starts failing in our country," Curbelo told CNN's "New Day" Thursday morning.

However, candidates and outside groups in other competitive races where Republicans' primary concern is turning out their base are also airing ads stoking fears about the group of migrants.

The Congressional Leadership Fund, the House Speaker Paul Ryan-aligned super PAC, launched an ad in Minnesota's 1st District -- a largely pro-Trump district that is among the GOP's best chances of flipping a House seat -- casting Democratic candidate Dan Feehan as "weak on border security, soft on crime."

"A caravan of illegal immigrants marching on America. Over 7,000 strong, the caravan is full of gang members and criminals," a narrator says. It has aired 124 times, per Kantar/CMAG.

In South Carolina's 1st District, Republican Katie Arrington highlights "an MS-13 killer arrested in the Low Country; a caravan of illegal immigrants marching on our border; Democrat Joe Cunningham, campaigning with the sanctuary city mayor of L.A.; the Pelosi agenda, open borders, undermining law enforcement." It has aired 125 times, per Kantar/CMAG.

A GOP group in Texas aired an ad accusing Democratic Rep. Beto O'Rourke, who is challenging Republican Sen. Ted Cruz, of cheering on the migrants. "The caravan is coming, some say criminals among them. But there's Beto O'Rourke, cheering them on," a narrator says

Two other Republican Senate candidates, state Sen. Leah Vukmir in Wisconsin and Corey Stewart in Virginia, have also advertised about the "caravan." Stewart's ad has run 469 times, per Kantar/CMAG.

In Kansas, Republican gubernatorial candidate and staunch Trump ally Kris Kobach uses footage of Fox News personality Tucker Carlson discussing the group of migrants growing "more massive by the day."

What those candidates all have in common: They need to jolt the conservative base before Tuesday's midterms. In Blackburn and Cruz's cases, both will win if Republicans turn out to vote. The same is true in Minnesota's 1st District, where Republican Jim Hagedorn hopes to win the retiring Rep. Tim Walz's seat. In Vukmir and Stewart's cases, both are underdogs worried that Republican voters will sit out the race.

On most of the map -- especially the states and districts where the partisan makeup is more balanced -- Republicans have generally not made the "caravan" their focal point in the closing days of the midterms. Still, most aren't displeased to see Trump driving a cultural message of fear.

"It's incendiary, I get it," one Nevada Republican said of the Trump ad. "It's a turnout game, and it fires up people on both sides."