New Hampshire Gov. John Lynch and Sen. Harry Reid of Nevada might want to take him to dinner. But John Edwards can't be happy with Vilsack, who leaves office as governor in January.
By entering the Democratic White House race, Vilsack has greatly devalued his own state's first-in-the-nation caucuses and scrambled the deck, at least strategically.
That is a gift to Clinton, the Democratic frontrunner for 2008, because that first contest could be one of the more difficult ones for her.
But it is a lump of coal for Edwards, the party's 2004 vice presidential nominee, who finished second in the Iowa caucuses then, and needs a bump from them in 2008.
It means that Lynch's New Hampshire primary will take on even more importance than usual in picking the Democratic nominee.
And Nevada, which moved its caucuses into the void between Iowa and New Hampshire, will be hosting more candidates. That's because with Vilsack, a long shot for the nomination in the race, the Iowa results will be taken with a rather large grain of salt.
That's a welcome development for Clinton, who will have more money and endorsements than she will need should she run.
What she won't have enough of is time.
As the frontrunner she will have to run a high-class, 50-state campaign which, by necessity, will limit the amount of time she can spend in Iowa. Other candidates without a national following can concentrate on a few early states.
Well-known, well-financed frontrunners who lose their party's nomination don't fail because they get knocked off in one of the big states with lots of delegates that come after the first round of small-state contests.
If they lose, they lose because of a disappointing showing in Iowa New Hampshire primary, which give candidates without those assets a chance.
In those states, candidates are expected to visit living rooms and Rotary clubs to deal with voters on a grassroots level. That puts a premium on a candidate's time, and his or her ability to motivate activists to lobby their friends and neighbors.
This is not to say that Clinton won't win the Iowa caucuses, or survive a loss there and still win the nomination. Ronald Reagan lost the caucuses in 1980 but won the Republican nomination and the presidency.
Yet, Iowa has been shaping up as a potential problem for her. A recent Des Moines Register poll of state Democrats found Edwards leading. And the head of the Iowa Democratic Party recently told FOX News that Clinton had not yet begun the kind of painstaking organizational work required to win the caucuses.
But now, whatever the Iowa results, the verdict will be suspect because of Vilsack's presence. Since politics is the ultimate zero-sum game, other states will see their candidate selection clout grow.
New Hampshire's lead-off primary is the obvious beneficiary, not that it wasn't already top dog. Democratic Gov. Lynch, if he chooses, could become a kingmaker, since his endorsement and organization could make or break a candidate there.
When the Democratic National Committee, at Senate Democratic leader Reid's strong urging, inserted Nevada's caucuses between Iowa and New Hampshire, it was not clear just how large a difference this change would make.
But with the Iowa results potentially tainted by Vilsack's candidacy, Nevada becomes a much more important stop on the caucus and primary tour. It is unclear how that state's politics, featuring a Democratic electorate less liberal than in Iowa or New Hampshire, will affect the nomination fight, but it will be an additional factor to consider.
And, most importantly, unlike in those two other states that have been vetting potential presidents for decades, Nevada Democrats who take part in the caucuses will not be professional voters accustomed to candidate hand-holding.
None of this is in stone. However, the candidacy by Vilsack, a well-regarded but little-known figure, will surely have implications for how all of the presidential aspirants run their race.