WASHINGTON — An early need for a lot of money and even more supporters in the 2008 presidential election is driving White House hopeful Mitt Romney and other contenders to start their campaigns before the first primary date is even set in stone.

While it is not that unusual for the presidential season to start around this time, experts say presidential candidates will need to find a balance to keep voters interested and keep themselves in shape for what is likely going to be a very long campaign.

Romney, the former governor of Massachusetts, will formally announce his candidacy in Michigan on Tuesday, then immediately hit Iowa, South Carolina and New Hampshire to meet with residents over the following three days. He already has visited the three early caucus and primary states numerous times in the past few weeks and has kept a busy travel schedule.

"The stamina that's going to be required of the candidates is going to be enormous," says Lewis Wolfson, a professor emeritus of communication at American University in Washington, D.C. "I think we are going to have 'political sickness.'"

It will be at least 10 months before a voter casts a ballot in a 2008 presidential primary, yet a number of unusual factors in this election cycle have forced the serious contenders to hit key states early and start organizing to show they are in it for the long haul.

This is the first presidential election since 1952 in which the sitting president or vice president will not be running for the nomination of either party. So far there are about 14 Republicans and 10 Democrats formally running, still testing the waters or on various lists of potential candidates that seem to be constantly changing.

Romney, 59, touts his time as governor and his experience in running the 2002 Winter Olympic Games in Salt Lake City as part of his qualifications for the Oval Office. As a member of The Church of Jesus Christ of Latter-day Saints, he is the fifth Mormon to seek the presidency, and he highlights his conservative values as a Mormon to align himself with conservative voters — although some are questioning whether the Christian right, particularly evangelicals, will vote for a Mormon.

Primaries in motion

Dates have been set for some important primaries and other key contests, but others are shifting targets.

The Iowa Caucus will take place Jan. 14, 2008.

The New Hampshire primary is scheduled for Jan. 22, 2008 — but that date could change.

South Carolina will be the first Southern primary, held soon after the New Hampshire primary.