Passed over for the chance to serve as vice president in the Obama administration, Sen. Evan Bayh now finds himself in a peculiar position: serving as something of the loyal opposition within his own party.

From the Senate side, Bayh has lined up with the Blue Dog Democrats of the House in attempting to slow down President Barack Obama's frantic efforts to ram through an expensive national health-care plan. He's also complained about this year's explosion in the deficit and voted against the federal stimulus package.

Bayh certainly has remained loyal to Obama, who in 2008 became the first Democratic presidential candidate to carry Indiana in more than 40 years. Indiana's junior senator rode with the president to the Elkhart area this week to join in the announcement that stimulus money would be used to fund battery and electric manufacturing in the state.

As a Democrat, Bayh has always been in the center-right of his party's ideological spectrum. He avoided tax increases when he was Indiana governor in the 1990s and looks for middle ground on almost any issue.

With a popular new president in the White House, Bayh has faced pressure to cave in on big spending schemes. But Bayh has resisted, partly because it fits with his approach to government and partly because he has his own political future to consider.

Indiana may have gone for Obama in 2008, although by a narrow margin, but the state for the most part is still fiscally and culturally conservative. Bayh is too astute a politician to forget that.

Other Indiana Democrats, including Reps. Baron Hill and Brad Ellsworth, also stand to the right of the national party. But the balance is especially tricky for Bayh if he's to retain any hope of making a presidential run in 2016. Too far left and he loses his Indiana base. Too far right and he won't play well in Democratic primaries.

Although it's in the still-distant future, Bayh would be only 60 years old in 2016, and the party, given that Vice President Joe Biden is unlikely to seek promotion, will be in need of a new standard bearer. By that time, the nation may be ready for an Evan Bayh-style moderate.

(Russell B. Pulliam, journalist, book author, associate editor and columnist at The Indianapolis Star, is a syndicated columnist, whose columns focus on topics ranging from politics to social issues to family life. He may be contacted at: russell.pulliam@indystar.com)