Washington (CNN) - Tim Kaine is the first to show his money in what could be one of the most expensive Senate battles of 2012.
The former Virginia governor and former Democratic National Committee Chairman's campaign will announce Tuesday that it has raised $2.25 million since forming on April 5, with more than 4,600 supporters making contributions.
"Tim Kaine has laid out an optimistic vision of bringing Virginia answers to Washington to help address serious national problems. We are pleased with how many people are responding to this campaign in its first weeks," said Kaine Press Secretary Brandi Hoffine, in a statement.
Tapping into voter unease over the nation's unemployment level and the country's massive budget deficit, Hoffine added that "our primary focus for the coming months will be building on our strong network of grassroots supporters who have already committed to helping elect Governor Kaine to the U.S. Senate and making sure every Virginia voter has the opportunity to hear his plans for creating jobs, growing our economy and restoring fiscal discipline in Washington."
Kaine is hoping to succeed Sen. Jim Webb, a fellow Democrat, who announced in early February that he would not run for a second term next year.
No word yet on how much former Sen. George Allen raised in the second quarter. Allen, who also served as Virginia governor from 1994 to 1998, was upset by Webb in 2006 when he ran for re-election to the Senate. Allen, who announced his bid for his old seat on January 24, raised $1.5 million in the first quarter of this year. The deadline to report numbers for the April through June period is July 15.
A GOP source told CNN that about a quarter of the money raised by Kaine came through ActBlue, which describes itself as "the online clearing house for Democratic action."
"As expected, liberal special interests have begun lining up to support and fund Chairman Kaine's campaign, including more than half a million dollars from the liberal website ActBlue alone," said Allen Campaign Spokesman Bill Riggs. "The reason is clear: they know that Chairman Kaine would be a reliable vote in the Senate for President Obama and the Washington Democrats' pro-spending, pro-union, pro-big government policies that he championed as Chairman of the Democratic National Committee."
"ActBlue is hardly a liberal special interest group - it's simply a way for Democratic donors from all walks of life to donate to their chosen candidates," responded Adrian Arroyo, ActBlue Director of Communications. "The fact that Mr. Riggs sees the transparency ActBlue offers as a threat and an opportunity to fearmonger says more about the Republican approach to fundraising than it does about our organization."
While Kaine faces no serious primary rivals at this time, Allen will have to contend with some conservative opponents. One of them, Richmond-area Tea Party activist Jamie Radtke, raised $150,000 in the first quarter.
A Quinnipiac University poll released last week indicated that a possible general election matchup between Kaine and Allen is a dead heat, with Kaine at 43 percent and Allen at 42 percent. Two of the top non-partisan political handicappers, the Cook Political Report and the Rothenberg Political Report, both characterize the contest for the open Senate seat as a toss up.
The Quinnipiac poll also indicated that Virginia voters are split at 48 percent on whether they approve of the job President Barack Obama is doing in the White House. In 2008, Obama became the first Democrat to win the state in a presidential election since 1964, capping a decade long streak of statewide victories by his party in the commonwealth. But Republicans won back the governor's office in 2009, in a landslide victory, and captured three Democratic held House seats in last year's midterm elections.
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