Republican presidential candidate Senator John McCain (R-AZ) holds a news conference with Utah Governor Jon Huntsman (not pictured) and former Governor of Massachusetts Mitt Romney (R) at the Million Air F.B.O. in Salt Lake City, Utah, March 27, 2008. Romney is at the top of the vice presidential prospect list for Senator John McCain. (Xinhua/Reuters Photo)

WASHINGTON, July 1 -- Former Massachusetts governor Mitt Romney is at the top of the vice presidential prospect list for Senator John McCain, the presumptive Republican presidential nominee, the Politico website reported Tuesday.

"Romney as favorite" is the hot buzz in Republican circles, and top party advisers said the case is compelling, it said.

One of the chief reasons that Romney is looking so attractive is his ability to raise huge amounts of money quickly through his former business partners and from fellow members of the Mormons.

Sources close to McCain tell Politico that they believe Romney could raise 50 million U.S. dollars in 60 days.

Romney's other advantages include the fact that he is squeaky-clean and fully vetted by the national media.

Moreover, he has presidential looks and bearing and immediately would be a strong campaigner who could be trusted to stay on message.

In addition, his family's Michigan roots would help in a swing state that went Democratic in 2004.

However, lack of personal charm could be Romney's biggest disadvantage, which was evident in this year's Republican presidential primaries.

Two other names are also in the top tier of McCain's potential running mates.

They are Rob Portman, a former congressman from Ohio and White House budget director and Senator John Thune of South Dakota.

Then there's a second tier of candidates who are less likely, but possible: former Pennsylvania governor Tom Ridge, Florida governor Charlie Crist, Minnesota governor Tim Pawlenty and Rep. Eric Cantor of Virginia.

If McCain is far behind Barack Obama, the presumptive Democratic presidential nominee, later this summer, he could do something truly unorthodox such as pick his strong supporter Senator Joseph I. Lieberman, who was the Democrats' vice presidential candidate back in 2000.