Rick Perry and Mitt Romney both lead President Obama in the critical swing state of Virginia while the Senate race between former Virginia Gov. Tim Kaine (D) and former Sen. George Allen (R-Va.) is all but tied, according to a poll released Monday afternoon by Roanoke College.

Romney leads Obama by 45 percent to 37 percent, while Perry leads Obama by a narrower 42 percent to 40 percent, within the poll's margin of error. The president won the state with 53 percent of the vote in 2008, making him the first Democratic presidential candidate since Lyndon Johnson to win there.

In the Senate race, Allen is up on Kaine by a narrow 42 percent to 39 percent, with 19 percent undecided.

The state could be a major national bellwhether next year: If Obama and Kaine win there it makes it much more likely Democrats will hold both the Senate and the White House, but if they lose both become much more challenging. Kaine and Allen are running to replace retiring Sen. Jim Webb (D-Va.), who beat Allen six years ago and is retiring after his first term.

The poll of 601 Virginia residents was conducted from Sept. 6-17 and has a margin of error of plus or minus 4 percent.