The earliest significant candidate to launch their candidacy was Mike Gravel in April 2006. However, for the most part, the race for the 2008 presidential nomination did not truly begin in earnest until after the 2006 midterm elections. Between November 2006 and February 2007, eight major candidates opened their campaigns: Joe Biden, Hillary Clinton, Chris Dodd, John Edwards, Dennis Kucinich, Barack Obama, Bill Richardson, and Tom Vilsack. Potential candidates John Kerry, Al Gore, Russ Feingold, Evan Bayh, Tom Daschle, Wesley Clark, Sam Nunn, Mark Warner, and Al Sharpton reportedly considered running but ultimately declined to seek the nomination. Vilsack dropped out in February 2007.