NASHVILLE - A Republican super PAC joined with Republican U.S. Senate candidate Marsha Blackburn on Tuesday and launched its own attack ad seizing on President Donald Trump's rhetoric about a migrant caravan headed to the U.S. border in order to slam Bredesen.

Blackburn is already airing a similar ad as she and Bredesen battle to replace retiring Republican Sen. Bob Corker of Chattanooga in next Tuesday's election.

Meanwhile, Bredesen's campaign, is already up with its own TV spot touting how as governor he sent Tennessee National Guard troops to the Mexican border to support a 2006 crackdown on illegal entry into the U.S. Bredesen's campaign.

Bredesen's campaign accused both the Senate Leadership Fund and Blackburn of resorting to "fear mongering" in the campaign's final week.

The Senate Leadership Fund, a GOP super PAC aligned with Senate Majority Leader Mitch McConnell, R-Ky., earlier Tuesday went up on the air with an ad similar to one being run by U.S. Rep. Blackburn's Senate campaign.

SLF's 30-second spot begins with black-and-white images of people, presumably immigrants, as a narrator warns "7,000 illegal immigrants marching on America, including gang members and criminals. 

"But," the male narrator continues, Phil Bredesen says " as the ad cuts to partial comments Bredesen recently made to a Kingsport television station where he said "a few thousand very poor people going to our border is not a threat, it's not a threat to our security."

The announcer quickly comes back to say: "Phil Bredesen strongly opposes President Trump's border wall. Now, a caravan is coming. Yet Bredesen is too liberal to care" before shifting back to Bredesen saying "it's not a threat to our national security."

It comes as Trump, scheduled to hold a Chattanooga rally for Blackburn on Sunday, doubles down on immigration in the days before next Tuesday's midterm election. 

The president now says he wants to order an end to the constitutional right to citizenship for babies born in the U.S. to non-citizens. 

But a number of legal experts and now U.S. House Speaker Paul Ryan, R-Wisc., say he can't achieve that through executive order. 

"Well, you obviously cannot do that," Ryan told Kentucky talk radio station WVLK Tuesday. "You cannot end birthright citizenship with an executive order."

Blackburn's ad, aimed at fueling concerns over illegal immigration, features a female announcer warning that "a caravan of 14,000 illegal immigrants is marching on America." It quickly shifts to Bredesen's comment that "a few thousand very poor people is not a threat "

The narrator comes back, saying, "Gang members, known criminals. People from the Middle East. Possibly even terrorists. Phil Bredesen?" before shifting again to Bredesen's remarks.

In his interview with WCBY-TV, Bredesen told the station he wants stronger security on the U.S. but believes concerns about the caravan are overblown.

"We're the strongest country in the world and a few thousand very poor people going to our border is not a threat to our security," Bredesen told the station.

Bredesen has also said he doesn't think Trump's proposed $70 billion border wall is practical and that needed border security can be achieved through technology and other less-expensive means.

The former governor's own new ad features a male narrator who says "actions speak louder than words. In 2006 when the president said he needed help to secure the border, Tennessee Gov. Phil Bredesen didn't wait to be asked. And he didn't play any politics.

"Gov. Bredesen took immediate action and sent 1,600 TN National Guard volunteers to the border. Then Gov. Bredesen went to the border to support them," the narrator adds as images shift of photos taken of Bredesen visiting Guard members and viewing the Arizona/Mexico border. "Phil Bredesen - because we need action in the Senate."

Blackburn previously attacked Bredesen on undocumented immigrants, accusing him in an ad of having "lured illegal immigrants to Tennessee" by offering them driver certificates.

"Now, Bredesen opposes President Trump's immigration ban. And Bredesen admits, 'I don't believe the wall is the right answer,'" the Blackburn ad said.

Before Bredesen became governor in 2003, the state already had a law on the books that allowed undocumented immigrants to obtain Tennessee driver licenses. 

After Bredesen became governor, the Bush administration raised concerns that the licenses could be used as identification to board planes, a sensitive issue after the 9/11 terror attacks. 

The state moved to certificates that stated the cards could not be used for identification. Bredesen said that was the solution recommended by the Bush administration. But he and state lawmakers later moved to repeal certificate issurance in 2007 amid concerns the program spurred illegal immigrants to come to Tennessee.

PolitiFact, a nonpartisan group, last week rated the Blackburn ad "Mostly False."

"Blackburn said that Bredesen 'lured illegal immigrants to Tennessee' by offering a driver's certificate for the undocumented. The one accurate part of the claim is that people came from out of state and fraudulently applied for both certificates and full driver's licenses.

"After that, the claim begins to break down," PolitiFact noted, adding that "Bredesen swapped a more lenient licensing law signed by his Republican predecessor for a less useful certificate that could not serve as official identification and lasted for only a year.

"To pin the law to Bredesen ignores that nearly every Republican lawmaker approved that change," the organization said.

Contact Andy Sher at or 615-255-0550. Follow on Twitter @AndySher1.