Republican presidential candidates Sens. Ted Cruz (Texas) and Marco Rubio (Fla.) on Sunday doubled down on their opposition to the Senate's confirming any Supreme Court nominee President Barack Obama picks.

WASHINGTON -- If Sen. Marco Rubio (R-Fla.) is elected president in November, remember this Sunday as the day he said he wouldn't try to get the Senate to confirm a Supreme Court justice in his last year in office.  

Rubio, who was making the rounds on the Sunday talk shows the morning after he debated his five opponents for the nomination, was pressed repeatedly on how he could justify the argument he and his Senate GOP colleagues were making. The Senate, that argument goes, should not act on President Barack Obama's planned nomination of a justice to replace Antonin Scalia, who was found dead Saturday. 

Republicans have tried to distinguish Obama's position from that of former President Ronald Reagan, who had his Supreme Court nominee, Justice Anthony Kennedy, confirmed in February of 1988, the last year of Reagan's second term. But Rubio told George Stephanopoulos on ABC's "This Week" that he would "recognize... that precedent that's been set over the last 80 years" and not put a justice on the bench if he, as president, is not going to be held accountable for his pick at the ballot box.

STEPHANOPOULOS:  So if you're elected president, will you promise not to make an appointment in your final year?

RUBIO:  Yes, well, I'm not saying the president can't make an appointment. I'm saying we're not going to move forward on it in the Senate. And that has been the practice now for over 80 years. 

STEPHANOPOULOS:  So you're saying he should?

RUBIO: He -- well, he's done. I'm not -- he has the legal right to do it, but -- and -- and as president, I would recognize that precedent, and the precedent that's been set over the last 80 years has been that, in the last year of a president's term, and in a second term especially, there should not be Supreme Court nominees put into lifetime positions for a president that you're not going to be able to hold accountable at the ballot box.

Rubio told Chris Wallace on "Fox News Sunday" that "if this was early in [Obama's] second term, that would be one thing," and that "perhaps this would be a different discussion" if Obama were nominating a justice three or four months ago. 

Rubio's logic was echoed by Sen. Ted Cruz (R-Texas), one of his rivals for the nomination. Cruz told NBC's Chuck Todd, who hosts "Meet the Press," that the Senate does not have an obligation "to at least go through the process and have an up or down vote" on Obama's nominee. "It has been 80 years since a Supreme Court vacancy was nominated and confirmed in an election year," Cruz said.

The distinction the Republican candidates appear to be making is that a president should not be able to nominate AND confirm a Supreme Court Justice, since Reagan nominated Kennedy in November of 1987 but had him confirmed in 1988. 

"There is a long tradition that you don't do this in an election year," Cruz explained. "And what this means, Chuck, is we ought to make the 2016 election a referendum on the Supreme Court. I cannot wait to stand on that debate stage with Hillary Clinton or Bernie Sanders and talk about what the Supreme Court will look like depending on who wins."