Their weakest hand is clearly in Nebraska. Kerrey was a liberal senator with no great accomplishments who retired from politics in 2001 in order to be president of the New School in New York City, where he lives in Greenwich Village. He has turned more hard-left ever since, saying in a videotaped interview, "The longer I live (in New York), the further left I get on health care."
If Kerrey was known for anything in his Senate days, it was for delivering speeches so filled with contradictions that it was hard to discern what he was saying. He could pop off with remarks that embarrassed his Democratic supporters and party leaders.
During the Clinton years, he was quoted in a lengthy profile in Esquire magazine that "Clinton is an unusually good liar. Unusually good."
In an interview with me in his Senate office in 1995, he said many of the GOP's Contract With America reforms the Republicans were voting for were good for the country, that Democrats would have to support them, and that Clinton was guilty of "cooking the books" in his budget proposals.
Veteran election handicapper Stuart Rothenberg says: "Kerrey deserves to be taken seriously. But skepticism is warranted. After all, he's been out of the state for years, has been mentioned as a potential candidate in New York and has already flip-flopped about his interest in the Senate race."
Nebraska, if anything, is even more conservative than it was when Kerrey held his Senate seat. Obama won less than 42 percent of the vote there in 2008, and Kerrey says he has no intention of even living in his home state. If he wins, he will probably reside in Washington. Polls already show him down by double-digits.
"Times have changed, and that makes Kerrey an even longer shot in Nebraska," Rothenberg said in a recent analysis. He scores the race "Republican Favored."
Maine is another case entirely. While its two senators are Republican, as is its governor, both House members are Democrats, and Obama carried the state by nearly 58 percent of the vote.
Rep. Chellie Pingree, a dyed-in-the-wool liberal, had led in the polls for the Democratic Senate nomination, but after King's entry, she reluctantly withdrew her candidacy.
A recent Public Policy Polling voter survey showed King with a narrow lead in a three-way race.
King, a popular former two-term governor, seemed to straddle both parties through much of his career, but has made it clear in the last decade that he was always in his heart and soul a Democrat. He supported Massachusetts Sen. John Kerry for president in 2004 and Obama in 2008.
Still, this latest deal showed that Reid isn't playing by the usual rules in this year's Senate races and will do just about anything to hold on to his powerful post. Republicans are crying dirty tricks.
"This is just the latest back-room deal we've seen from national Democrats, and it adds to the cynicism that voters in Maine and around the country rightfully feel toward those running Washington these days," said Rob Jesmer, executive director of the National Republican Senatorial Committee.
Right now, the question for Kerrey and King is simply this: Are you the candidate of the people of your state, or the candidate of the party bosses in Washington?