Virginia Del. Bob Marshall will run for the GOP Senate nomination, adding a new wrinkle to a race likely to be decided between two political heavyweights.

But few political observers in the state give Marshall much of a chance to defeat George Allen, a former governor and Senator who is on a collision course for November with former Gov. Tim Kaine (D).

“I just think that, ultimately, even though there is a pretty good conservative stream in the primary electorate, I just think he’s too fringe to really steal much away,” one GOP strategist with experience in the state said. “I don’t think he has much impact on Allen.”

At the 2008 state party nominating convention, Marshall came within 100 votes of former Gov. Jim Gilmore out of more than 10,000 votes cast, even though Gilmore outspent him by a sizeable margin. Convention delegates are generally more conservative than the overall primary electorate, which helped Marshall and kept then-Rep. Tom Davis out of the race.

Virginia Republicans voted in November 2010 to hold a primary this year, a boost for Allen, who will have a significant financial advantage and ability to reach voters across the state. Allen’s campaign announced Tuesday that it raised $1.1 million in the fourth quarter, leaving him with $2 million in the bank.

Allen already has a few challengers for the June primary, including tea party leader Jamie Radtke, minister E.W. Jackson and attorney David McCormick, though none have so far competed with Allen financially or generated much attention. Kaine and Allen faced off last month in a two-person debate, as polling and fundraising eligibility guidelines kept the others from participating.

Unlike Radtke, who has lambasted Allen over his Senate tenure, Marshall said in an interview that if he ran his campaign would not focus on a comparison of records with his primary opponents.

“It would be what I could do vis-à-vis Tim Kaine,” Marshall said. “In other words, I’m not contrasting myself to any Republican candidate.”

Marshall isn’t expected to keep up with Allen in the money race, but some believe the socially conservative state legislator can at least push Allen to take stands on issues that Kaine could use as ammunition in the general election.

“Even with Radtke in the race, Allen’s already taken a stand on behalf of a ‘personhood’ amendment,” which Marshall sponsored in the Legislature, Virginia political analyst Bob Holsworth said. “Marshall has bills before the Assembly already this year about guns on college campuses.”

Republican strategists are skeptical that Marshall is any real threat to Allen’s nomination. Allen has built a strong campaign team, has raised more than $4.5 million and has been touring the state nonstop for well more than a year.

While Allen likely would rather not have Marshall in the race, Holsworth said Marshall “is not going to come up with the kind of organization and financing that Allen has. Marshall is very much dependent on his skill garnering media coverage.”

Marshall reiterated in an interview earlier this week that his campaign would focus on the public policy clashes he’s had with Kaine over the past six years. Marshall is also a former Congressional staffer who worked on Capitol Hill for both Republicans and a Democrat, then-Rep. John Blatnik (Minn.).