CONCORD – Sen. Joseph Biden filed as a candidate in the New Hampshire presidential primary yesterday, and endorsed the election as a crucial first stop in any candidate's march to the White House.

"Without the New Hampshire primary and the Iowa caucus, there is no level playing field. The nomination in both parties would go to the highest bidder -- the person who can raise the most money from the most interest groups," he said.

He credited state voters for asking "serious and consequential questions" of all candidates.

Former U.S. Sen. Mike Gravel, D-Alaska, also filed yesterday.

Biden, 64, a Delaware Democrat, has been in the U.S. Senate since he was elected in 1972 at the age of 29. He has served on the Senate's Foreign Relations Committee for three decades, and became its chairman in January. He explored a run in the 1988 primary, but did not file as a candidate.

He said he thinks his foreign policy experience will boost his candidacy, since the Iraq war is the major issue on the minds of most voters, especially Democrats.

His plan, which passed the Senate with 75 votes, would federalize Iraq by giving Sunnis, Shiites and Kurds their own semi-autonomous regions to govern, united under a single national government.

He said the plan, endorsed by all but one Iraqi leader, is by far the best way to end the war.

Pointing to a group of fourth-graders at the State House today, he said, "How we leave Iraq will determine, literally, not figuratively, whether they go back there." As for his chances in a race where polls show him lagging behind other big-name candidates, he said, "this is wide open -- absolutely wide open. This has been about money, name recognition and stardom." He said polls will not firm up for weeks.

"(New Hampshire) voters never make up their minds until it comes around the middle of December," he said. Early frontrunners have a history of falling by the wayside as the election date nears, Biden said.

Gravel, 76, was not invited to the most recent national debate among Democrats in Philadelphia.

He said he wants to restore more power to voters by giving them the ability to pass laws through referenda. Congress is so corrupted by money from corporations and special interests, he said, that its members are afraid to cross donors no matter what principle is at stake.

Admitting he has a long way to go to catch leading candidate in the race, he said "anything can happen in American politics."