The four presidential contenders entered Monday with a full-court press on the banks of the Chesapeake Bay a day before Maryland, Virginia and the District of Columbia host primary voting.

The region that is usually overlooked in primary voting due to its place on the primary calendar after Super Tuesday has become a central battleground for Democratic rivals Hillary Clinton and Barack Obama as they continue to try to rack up the convention delegates that will determine who gets the final nod at the August party convention.

In the latest overall totals in The Associated Press count, Clinton had 1,136 delegates to 1,108 for Obama. The totals include so-called superdelegates, which are party leaders not chosen at primaries or caucuses, free to change their minds. A total of 2,025 delegates is required to win the nomination.

GOP front-runner John McCain this week seeks to put the lid on the contest after a weekend that saw him lose decisively in two states to his only remaining rival, Mike Huckabee, who took Kansas and Louisiana. And McCain only won by a slim margin in Washington state, so slim that Huckabee has filed legal action to contest the ballot count.

The Democratic race, which has already seen several weekend events in Maryland and Virginia, continues at a feverish pace Monday in Democrat-heavy Maryland.

Clinton comes off embarrassing defeats in all four states that voted this weekend -- Louisiana, Nebraska, Washington state and Maine -- and hopes to regain her front-runner status with a shakeup that brings in a new campaign manager, Maggie Williams, to replace Patti Solis Doyle.

Clinton began the morning in the District, attending an event courting black women voters. She then was to travel to Baltimore suburbs where she planned on holding a rally before auto union worker, and will then break for the youth vote in Charlottesville, Va., home to the University of Virginia.

Her husband Bill Clinton will be active as well, splitting his time between Maryland and Virginia.

College Park, Md., home to the University of Maryland, has been a busy campaign event in the Washington, D.C., suburbs, hosting Huckabee Saturday, and Chelsea Clinton on Sunday. But the largest event likely will be a rally Barack Obama plans to hold Monday at the school's basketball arena before he heads to downtown Baltimore to hold another arena event.

After that, Obama plans to head to Chapel Hill, N.C., which holds one vote that could prove decisive in the nomination battle: that of former candidate John Edwards. Clinton met with Edwards last week, and both seek his endorsement.

The Republican contenders will spend most of their day in the redder state of Virginia., although McCain will kick his day off at his alma mater, the U.S. Naval Academy in Annapolis, Md.

Then he and Huckabee will be treading the same path in Richmond, Va., where McCain heads to next, and where Huckabee starts his day. Huckabee continues on to Virginia Beach, and then holds two events in rural Virginia.