(CNN) - It's expected to be one of the most high-profile Senate races this fall, but GOP candidate George Allen of Virginia has one more hurdle to cross before storming ahead in the race against Democratic opponent Tim Kaine.
In Tuesday's Republican primary, Allen faces a crowded field of Senate hopefuls in Virginia, though all of them trail far behind the former governor in recent polls.
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Republican voters will choose between Allen, state lawmaker Bob Marshall, tea party activist Jamie Radtke, and minister E.W. Jackson. A Washington Post poll released last month indicated Marshall was the most serious competitor against Allen, though he still had the backing of only 12% compared to Allen's 62% among voters.
While Allen attempts to shore up the Republican vote this week, his three opponents have nevertheless left their mark on the primary race by forcing the candidate to run further to the right in his campaign.
The candidate previously held the Senate seat before losing re-election in 2006 to Democratic Sen. Jim Webb, who's now retiring after one term.
Meanwhile, Kaine, also a former governor and the former Democratic National Committee chairman, is running unopposed.
In this year's first quarter, the Democrat reported having more money in the bank than his Republican opponent–$4.4 million to Allen's $2.7 million.
Along with a Senate race featuring two former governors, Virginia will be a political hotbed this fall in the presidential election as both President Barack Obama and Republican Mitt Romney vie for the crucial swing state.