WASHINGTON - Sen. John Kerry says he deserves a second chance if he decides to take another crack at becoming president. The Massachusetts Democrat, who lost to President Bush in 2004, said it is a basic principle that "Americans give people a second chance. And if you learn something and prove you've learned something, maybe even more so. Now, I don't know what I'm going to do yet. We'll make that decision down the road." Ronald Reagan twice unsuccessfully sought the GOP nomination for president before he got it — and won two elections for the White House. "John McCain, their leading candidate — didn't he get kicked around South Carolina by the same president because he wasn't patriotic enough as a prisoner of war? He's now their leading candidate for president," Kerry said of the Republican Party. " Richard Nixon seemed to get kicked around pretty badly both running for president and governor, turned around and came back and got elected president." Kerry faces a major challenge trying to convince Democratic activists that a recently defeated candidate can still carry his party's hopes for recapturing the White House. If Kerry runs, he would have to overcome other Democratic presidential hopefuls such as Sens. Hillary Rodham Clinton of New York, Joe Biden of Delaware, Russ Feingold of Wisconsin and Christopher Dodd of Connecticut. The list of potential opponents also could include New Mexico Gov. Bill Richardson, former Indiana Gov. Sen. Evan Bayh (news, bio, voting record), Iowa Gov. Tom Vilsack, and even Kerry's ex-running mate in 2004, former Sen. John Edwards of North Carolina.