It wasn't long after the death of Supreme Court Justice Antonin Scalia before Sen. Ted Cruz (R-Texas) seized the opportunity to formulate a new attack against Republican front-runner Donald Trump.
Cruz on Monday released a television ad titled "Supreme Trust," in which the narrator lists issues important to conservative voters -- "life, marriage, religious liberty, the Second Amendment" -- and doubts Trump's ability to preserve them.
"We cannot trust Donald Trump with these serious decisions," the narrator says. "We're just one Supreme Court justice away from losing them all."
The ad features footage of a 1999 "Meet the Press" interview featuring Trump, in which the business mogul says he is "very pro-choice."
Watch the ad above.
During an appearance on "Fox and Friends" Monday morning, Cruz reiterated his concerns that abortion restrictions and gun rights are on the line.
"He has been a liberal his entire life," Cruz told Fox News, noting that Trump has made contributions to Sen. Chuck Schumer (D-N.Y.), Senate Minority Leader Harry Reid (D-Nev.) and Secretary of State John Kerry.
"If you vote for Donald Trump, we will see the Second Amendment written out of the Constitution, because one liberal justice will do that," Cruz added.
Immediately following the news of Scalia's untimely death, conservatives took to social media to express their refusal to confirm any nominee President Barack Obama brings up to fill the vacancy during his last year in office. The Republican presidential hopefuls brought their fervor to the debate stage in South Carolina hours after Scalia's passing, agreeing Obama shouldn't nominate the next Supreme Court justice.
"I think it's up to [Senate Majority Leader] Mitch McConnell and everybody else to stop it. It's called delay, delay, delay," Trump said.
Trump addressed Cruz's attacks during a press conference in Charleston, South Carolina, on Monday afternoon.
He repeatedly called Cruz a "liar" and said he would bring a birther lawsuit against Cruz if the senator doesn't apologize.
"He'll apologize, but I don't want an apology after the election. I want it before," Trump said. "I will bring that lawsuit if he doesn't apologize."
Trump released a statement in conjunction with the press conference, responding "to the lies of Senator Cruz" and threatening legal action. In the statement, Trump called Cruz "totally unstable," saying "it is hard to believe a Christian could be so dishonest and lie so much."
Republican voters in the state will head to the polls Saturday to make their pick in their party's primary. Trump has a safe lead over Cruz and the other Republican candidates going into the election, according to HuffPost Pollster, which aggregates all publicly available polling data:
This article has been updated with Trump's comments from Monday afternoon.