Generally, after a hard-fought Senate confirmation vote to a top administration post, there’s an all-around shaking of hands, backslapping reassurances that none of the criticism was personal and pledges of varying sincerity to work together for the good of the country.

Instead, Chuck Hagel becomes secretary of defense with a sizable number of his former fellow Republican senators waiting for him to slip up and fail. Little surprise there.

John Cornyn of Texas, the Senate’s second-ranking Republican, offered this less-than-confidence-building judgment: “He will take office with the weakest support of any defense secretary in modern history, which will make him less effective in his job.”

Actually, it’s worse. Hagel was confirmed Tuesday — after protracted and acrimonious debate and an attempted filibuster — by a 58-41 vote, the smallest margin since the defense-secretary post was created more than 60 years ago. Only four Republicans voted for Hagel, a onetime two-term GOP senator from Nebraska. Neither of Georgia’s senators, Johnny Isakson (R-east Cobb) or Saxby Chambliss (R-Moultrie) voted for Hagel.

It didn’t help Hagel’s candidacy that he was sharply criticized by many Jewish groups for his lackluster support for Israel in the past. It also did not help that he was publicly endorsed as the best candidate for the job by Iranian Premier Mahmud Ahmadinejad.

An early priority for Hagel will be building strong relations with the House and Senate armed services committees. It will be an uphill task with the Senate, whose committee has two of his most severe critics: John McCain of Arizona and James Inhofe of Oklahoma.

Of course, Hagel can silence critics by successfully rising to the many challenges of his job. He won’t have to wait long for that opportunity. Today he faces his first crisis: He must somehow come up with $46 billion in spending cuts, about 9 percent of the Pentagon budget, compressed into the seven months between now and the end of the fiscal year on Sept. 30.

And this is after three months in which the Pentagon’s top brass and outgoing Defense Secretary Leon Panetta have been telling anyone on Capitol Hill who’ll listen that the cuts will leave the country with a “hollowed out” military because of cutbacks in training, maintenance and procurement and the furloughs of civilian personnel.

Of course, this gets us to another of President Obama’s main reasons for nominating Hagel in the first place: his party affiliation. He’s a Republican. Thus, as the axe inexorably falls on Pentagon spending in the sequestration process, and/or in Obama’s inevitable Defense drawdown, he will be able to point at Hagel and describe the cuts as “bipartisan” because they “have the support of the secretary of defense, who’s a Republican.”

That’s how the game is played in D.C.

The country deserves better.