Hanover, N.H. -- Former Vermont Governor Howard Dean said the crowded field of Democratic presidential hopefuls is playing nice so far, but the party chairman told Dartmouth College students Monday morning he doubts the civility will continue much longer.

For now, he says Democrats are presenting a relatively unified front on key issues, but he says things will get rougher before they get easier.

Dean said other states' plans to move their primaries earlier and closer to New Hampshire's first-in-the-nation primary can only increase the state's clout.

He said wins in early-voting states such as Iowa and New Hampshire will give candidates a boost going into what is being billed as "Super Duper Tuesday," Feb. 5.