CHICAGO (AFP)---Republican John McCain has settled on a running mate and will unveil his choice on Friday as he seeks to limit the expected poll surge from Democrat Barack Obama's nomination, reports said.
The Washington Post reported on its website that McCain would notify his vice presidential pick on Thursday before making a joint appearance with his chosen partner at an event in Ohio on Friday.
The Politico.com website also reported McCain had settled on his vice presidential candidate.
The reports came amid a fierce Republican grassroots push for a partner who will uphold conservative traditions as other factions lobby for a vice president with strong economic and security credentials.
Younger Republican contenders may also see their chances improve because of McCain's age -- at 72 he would be the oldest president inaugurated for a first term should he beat Obama in the November elections.
McCain' Friday announcement in the key battleground state of Ohio would help draw attention away from Obama's acceptance speech at the conclusion of the Democratic convention on Thursday.
Major rallies are also planned in two other battleground states -- Pennsylvania and Missouri -- ahead of the Republican convention in St. Paul, Minnesota which kicks off on Monday.
On the list of possible candidates is Joseph Lieberman, a close friend and constant companion on McCain's campaign trail. He is considered as a dark horse in the race for the VP pick.
A former Democrat who was Al Gore's running made in 2000, the four-term Connecticut senator, 68, had a falling out with his party over the war in Iraq and is now an independent with a hard-line foreign policy.
However, the first Jewish candidate on a presidential ticket still sits with the Democratic caucus and votes with the party on many issues.
Choosing Lieberman would play well against Democratic presidential hopeful Barack Obama's message of change and could help McCain win over independent voters attracted to his call to put aside partisan politics, especially in states with large Jewish communities such as Florida.
But the cost of alienate the party's core of social conservatives might be too high.
High on the list is former Massachusetts governor Mitt Romney, who lost to McCain in a bitter primary race but has since rallied aggressively on behalf of his former rival.
Romney attacked Obama on the sidelines of the Democratic convention in Denver Tuesday but played coy about his aspirations, telling reporters: "I have nothing for you on the VP front."
A self-made millionaire whose father was the governor of Michigan, Romney is also credited with saving the scandal-plagued Salt Lake City Winter Olympics, staged successfully in 2002.
"Governor Romney would help shore up (McCain's) perceived lack of economic experience," said Heath Hall, a senior policy analyst at the conservative Heritage Foundation think tank.
"Also Romney strategically helps as far as the states of Michigan, New Hampshire ... and the mountain states like Colorado, New Mexico and Nevada that have been viewed in play as well."
Another contender is Tom Ridge, who was the first secretary of homeland security under President George W. Bush and is also a former governor of Pennsylvania, a potentially decisive battleground.
While Ridge's security credentials would help win over independent voters, his support of abortion rights could alienate the Republican base.
Minnesota Governor Tim Pawlenty, who will be in Denver Thursday to help undermine the Democrats, is well-liked by conservatives for his anti-abortion stance and evangelical background.
But while the 47-year-old would bring youth and energy to the campaign, it is unclear if Pawlenty can really deliver Minnesota.
His lack of experience may also not play well against Obama's VP pick:
Senate Foreign Relations Committee Chairman Joseph Biden, a sharp debater whose decades in Washington will help offset criticism of Obama's lack of experience.
While it's important that McCain's VP candidate helps deliver votes, it won't be too hard to bring out the base on election day, said presidential historian Tom Whalen.
"All the McCain folks need to say is, look what the alternative will be, and that will scare up the base," Whalen said.
"Obama -- my God how many members of the electorate still think he's a Muslim?" Whalen said. "They don't have to say it but they know others in the party will do it for them."
