Republican voters again named Mitt Romney as their top choice for the 2016 race, according to a new Quinnipiac University national poll released today.

Despite adamantly opposing another go at the presidency, the former 2012 Republican presidential nominee and Massachusetts governor came out ahead, with 19 percent of the 707 Republicans surveyed saying they would vote for Romney if a Republican primary were held today.

Former Florida Gov. Jeb Bush was next with 11 percent, and New Jersey Gov. Chris Christie and Dr. Ben Carson each received 8 percent. All other Republican hopefuls fell below 6 percent, and 16 percent of voters were undecided.

But if Romney were out of the picture, Bush would jump a few points to 14 percent, followed by Christie at 11 percent and Carson at 9 percent, leaving 19 percent undecided.

Romney and his family have repeatedly said that another presidential run is out of the picture, but sources close to Romney's inner circle have said that it can't be ruled out entirely.

If he were to run, "he would be the last guy in the race," one source told CNN, with another source saying that if Jeb Bush and Chris Christie were running, Romney would be even less likely to enter the race.

If Jeb Bush were to back out, one former Romney adviser said it would increase Romney's chance of running by "about 20 percent."

Amongst Democratic leaners polled, Former Secretary of State Hillary Clinton stole the show, receiving 57 percent of the vote, followed by Sen. Elizabeth Warren of Massachusetts at 13 percent. If Clinton doesn't run, Biden gets 34 percent, followed by Warren with 25 percent.

A separate poll released this week also found Romney leading the pack of possible Republican contenders.

In the Bloomberg Politics/St. Anslem New Hampshire poll released Monday, Romney garnered 30 percent of the vote, amounting to a 19-point lead over other GOP contenders like Kentucky Sen. Rand Paul, who trailed at 11 percent. Christie received 9 percent and Bush 8 percent. Carson followed with 6 percent.