With Washington abuzz over speculation that John McCain will announce his running mate this week to take some of the focus off Barack Obama’s overseas travels, over a third of U.S. voters say Mitt Romney will be the Republican vice presidential candidate.

The former Massachusetts governor and one-time rival of McCain’s for the GOP presidential nomination was the top vote-getter with 36% in a new Rasmussen Reports national survey taken last Friday night.

Among Republicans, Romney is the leading choice by far: 50% say they think he is the best running mate, and 47% think he will be picked by McCain. He is the top vote-getter among unaffiliated voters, too, with 34% expecting him to get the nod.

Forty-four percent (44%) of likely McCain voters believe Romney is the best choice, with 45% sure he will be the one who is actually chosen for the vice presidential slot.

Among all voters, 11% think another Republican presidential hopeful and former governor, Mike Huckabee of Arkansas, will be McCain’s pick.

Ten percent (10%) say McCain will reach across party lines to name Connecticut’s independent Democratic Senator Joseph Lieberman, his own party’s vice presidential nominee in 2000, as his running mate.

Three governors known to be under consideration by the GOP candidate all registered in single digits – Florida’s Charlie Crist (7%), Louisiana’s Bobby Jindal (5%) and Tim Pawlenty of Minnesota (5%).

Twelve percent (12%) expect McCain to name someone else, and 14% are undecided.

Those surveyed were not asked to respond to the possible selection of former New York Mayor Rudy Giuliani and one-time Pennsylvania Governor Tom Ridge, whose names have emerged only in the last few days as serious GOP vice presidential contenders.

While vice presidential candidates seldom, if ever, make a significant impact at the polls, McCain’s choice is of more interest, given his age and the fact that it puts the running mate in position to succeed him as the GOP’s standard-bearer in a subsequent election.

Seventy percent (70%) of voters in the new survey, however, noted correctly that most of those elected vice president do not later go on to be president.

Obama is not expected to name his running mate until closer to the Democratic National Convention in late August.

Hillary Rodham Clinton, who only dropped out of the Democratic presidential race in early June, is expected by 24% of voters to be Obama’s choice for vice president. But 25% think he will choose someone else.

Fourteen percent (14%) think Obama will choose former Senator John Edwards of North Carolina, another of his rivals for the party’s presidential nomination.

Interestingly, the third most popular candidate, as in McCain’s case, is someone from the other party, in this case, Republican Sen. Chuck Hagel of Nebraska, whom nine percent (9%) think will be Obama’s pick. Hagel is currently traveling with Obama in the Middle East and Europe.

Eight percent (8%) think the Democratic presidential hopeful will select Indiana Senator Evan Bayh as his running mate, and seven percent (7%) think Virginia Governor Tim Kaine will be the one.

Voters were not asked about any other specific candidates for the Democratic position.

While 40% of Democrats now think Clinton is the best choice, only 28% expect Obama to make her his running mate. Clinton is the number one choice of unaffiliated voters, too, but only 17% expect her to be on the Democratic ticket.

Only 24% of likely Obama voters agree that she will be chosen, while 26% expect him to go with someone else.

Romney and Bayh are the leading candidates for vice president in their respective parties in the Rasmussen Markets at this time.

In a Rasmussen Reports survey in late June, 44% of Democrats said Clinton should be Obama’s running mate, down from 51% immediately after Obama clinched the nomination earlier in the month. Just 24% of unaffiliated voters said Clinton should be on the ticket while 52% disagreed.

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