Editor's note: This story has been updated throughout.
SENECA, S.C. — Ted Cruz is ratcheting up pressure on his Republican rivals to back up their accusations of dishonesty against his presidential campaign, challenging Donald Trump to follow through with an alleged threat to sue him.
"Donald, I would encourage you, if you want to file a lawsuit challenging this ad, claiming it is defamation, file the lawsuit," the U.S. senator from Texas said Wednesday here at a news conference in which he extensively disputed his opponent's allegations that he is running an unethical campaign.
Cruz said his campaign had received a cease-and-desist letter from Trump threatening legal action over a TV ad that says the billionaire cannot be trusted to appoint U.S. Supreme Court justices. The spot, like many Cruz's campaign has released, centers on a 1999 interview in which Trump described himself as "very pro-choice."
"Even in the annals of frivolous lawsuits, this takes the cake," Cruz said, suggesting Trump's legal team could be sanctioned for pursuing such a challenge.
Cruz made clear he wants Trump to follow through so he can formally argue why Trump's views on abortion are out of step with conservatives. If Trump does file the lawsuit, Cruz, the former solicitor general of Texas, said he looks forward to deposing the billionaire himself.
Trump responded to Cruz’s news conference by calling it a desperate ploy “by a guy who is tanking in the polls.” Trump also defended his anti-abortion credentials, calling himself “pro-life” and insisting he opposes taxpayer funding for Planned Parenthood as long as it performs abortions.
“Watching his campaign go up in flames finally explains Cruz’s logo,” Trump said in a statement, promising that any lawsuit he files will be legitimate. “Likewise, if I want to bring the lawsuit regarding Senator Cruz being a natural born Canadian I will do so. Time will tell, Teddy.”
Trump has previously threatened to sue Cruz over his eligibility to be president, though this time is different. In the cease-and-desist letter, which the Cruz campaign gave to reporters, Trump lawyer Jeffrey Goldman calls the ad libelous and threatens “immediate legal action” if the campaign does not take down the ad. Calling his argument “laughable,” Cruz lawyer Chris Gobel formally responded to Goldman by promising to air the ad “with greater frequency.”
Cruz cited four “data points” to support his ad’s suggestion that Trump would not pick anti-abortion jurists for the high court: his remarks in the 1999 interview, his suggestion that he would appoint his “abortion-supporting” sister to the Supreme Court, his donations to Democrats over the years and his comment at the most recent GOP debate that Planned Parenthood “does wonderful things.”
Cruz opened a new line of attack against Trump on the topic of his donations to Democrats, saying they specifically helped Democrats take control of Congress in 2006. Equipped with a poster detailing 30 Democratic candidates and groups Trump has contributed to, Cruz drew a direct link between the billionaire’s giving history and President Obama’s signature health care law.
“Donald Trump is a direct cause of Obamacare because if either house had remained in Republican control, Obamacare would’ve never passed,” Cruz told reporters.
Cruz also took aim at GOP rival Marco Rubio, whose campaign has tied Cruz to push polls in South Carolina as well as a fake Facebook page saying that U.S. Rep. Trey Gowdy, who has endorsed Rubio, no longer supports him. Cruz insisted Rubio’s claims are baseless, accusing him of resorting to Trump’s strategy of reflexively calling Cruz a liar.
“Marco Rubio is behaving like Donald Trump with a smile,” Cruz said, calling his Senate colleague desperate after a third-place finish in Iowa and a fifth-place finish in New Hampshire. “His campaign has not gotten the traction it wanted.”
Rubio's campaign fired back in a statement Wednesday evening, demanding that Cruz apologize to Gowdy. Rubio spokesman Alex Conant accused Cruz campaign officials of slandering Gowdy by questioning his skills as a former federal prosecutor after he drew attention to the Facebook page.
"Today's actions by Senator Cruz and those who speak for him are indicative of a campaign spiraling out-of-control in an all-out effort to win at any costs, even if it means sacrificing the Senator's integrity in the process," Conant said in a statement.
The escalation of Cruz's rhetoric against Rubio and Trump comes three days before South Carolina holds its first-in-the-South primary. Recent polls have shown Cruz jockeying for second place there with Rubio, while Trump continues to lead the GOP pack by wide margins.
The Palmetto State has particularly tested Cruz's vow to avoid mudslinging in the race for the White House. Asked if he was violating that promise with his fierce pushback against Rubio and Trump, Cruz insisted to reporters that he has "taken the high road" since the start of his campaign.
"I am not insulting anybody," Cruz replied. "I am responding with simple facts."
Disclosure: Planned Parenthood was a corporate sponsor of The Texas Tribune in 2011. A complete list of Tribune donors and sponsors can be viewed here.