"Rubio got to Washington and wrote the bill giving amnesty to illegals using Obama's talking points," a narrator says in the spot. "Marco Rubio burned us once. He shouldn't get the chance to sell us out again."
The spot then alternates between clips of Rubio defending the 2013 immigration bill he worked on with the so-called "Gang of Eight" in the Senate -- which would have created a pathway to citizenship for undocumented immigrants in the U.S. if they met certain criteria and paid a tax penalty -- and Obama.
It began airing in Greenville, South Carolina, on Tuesday evening, according to CMAG/Kantar Media, a company that tracks political advertising. It's the latest searing attack from Cruz in the ongoing fight between the two senators as they look for a strong showing in South Carolina.
Rubio on Wednesday continued to attack Cruz for being dishonest and politically calculating, saying the Texas Republican's behavior has been "disturbing."
Speaking to reporters in Mount Pleasant, South Carolina, on Wednesday, the Florida senator continued to push a narrative that his senate colleague does whatever is politically expedient.
"I've been saying for a while now that Ted unfortunately has proved that he is willing to say or (do) anything to get elected," Rubio said. "What we've seen in the last couple weeks is disturbing. ... It's been apparent especially in the last month."
Rubio hit Cruz for shady tactics on a number of fronts, including bringing up that the Texas senator's campaign told precinct captains in Iowa to tell caucusgoers that Ben Carson was suspending campaigning, as well as hitting him for robo calls unfavorable to Rubio and Trump. The Cruz campaign has denied any connection to doing the robo calls.
Rubio also said Cruz was mischaracterizing the Florida senator's record.
"I'm just responding, you can't let these things stay out there because they people think they are true," Rubio said. "They're not true."
The two senators have been feuding in recent weeks as they have drawn close in the polls in upcoming states, including South Carolina. Cruz has attacked Rubio's record on immigration, especially, and has brushed off accusations of lying.
"We are not in grade school where you just get to say, 'liar, liar pants on fire' and not respond to the substance," Cruz said in South Carolina on Monday, adding on "Fox and Friends" the same day, "I guess Marco's team has told him, 'Well, if anyone brings up your actual record, the fact that over and over and over again you've supported amnesty, just yell liar.'"
Rubio's campaign has made a concerted effort to keep the issue in front of voters, playing on Cruz's "TrusTED" slogan with puns like "BusTED" and "CalculaTED." The campaign sent a fundraising email to supporters Tuesday night using Cruz as a focal point, saying Cruz and his super PACs were engaging in "slimy smear tactics."
Both candidates are positioned to do well in South Carolina but both need to finish strong to keep their presidential hopes alive.
Cruz, who won the Iowa caucuses, is looking to pick up momentum to challenge front-runner Donald Trump. And Rubio, who stumbled in New Hampshire after a strong third place in Iowa, hopes to separate himself from the other candidates to convince voters he is best positioned to challenge Cruz and Trump.