WASHINGTON: Every election sets off a round of musical chairs on Capitol Hill. This year’s GOP sweep will shake up the Senate in particular, and there’s one plausible scenario that should make the Pentagon and contractors especially nervous, because it would put two champion attack dogs of oversight at the helm of the Senate Armed Services Committee: John McCain and Claire McCaskill.

My colleague Colin Clark has already written about McCain’s now-nigh-certain return to the SASC chairmanship, but the mention of McCaskill threw me. Several sources, though, say it’s pretty plausible. I first heard the scenario Friday during a panel discussion hosted by the Professional Services Council (PSC), a government contractors’ group.

“The conventional expectation that we would have the ranking member [be] Jack Reed,” said Alan Chvotkin, the PSC’s executive vice-president and counsel. “[But] he’s also eligible to be the ranking member on the Banking Committee” — finance being a major industry in Reed’s homestate, Rhode Island. So far the Senator has stayed studiously silent on his choice.

If Reed goes for Banking, Chvotkin continued, the next Democrat in line on SASC would be Florida’s Bill Nelson — “but Sen. Nelson also is in position to be the next ranking member on the Senate Commerce committee, which has NASA, [and] he’s a former astronaut heavily engaged in those kinds of Commerce Committee issues.” (Of course, Florida has plenty of military bases as well as the “Space Coast” around NASA’s Cape Canaveral, so the SASC chair may prove more powerful a lure than space sentiment for Nelson)

“If neither Mr. Reed nor Mr. Nelson, then Sen. McCaskill is third in line,” Chvotkin concluded. That means a McCain-McCaskill committee, he said. “Cue groans from all of us on the panel.”

PSC represents not just any federal contractors, but specifically service contractors, the ones in most direct competition with federal employees, so they’re used to be being bashed in hearings and take a dim view of what one panelist called “shoot-first oversight.” That said, as a former sex-crimes prosecutor and government auditor, McCaskill has hammered the Pentagon hard on classic “waste, fraud, and abuse” issues and on sexual assault in the ranks, helping drive major and often controversial reforms in how the military justice system handles such cases.

A McCaskill-McCain SASC would be a furious dynamo of oversight. McCain is famous — or infamous, depending on your perspective — for his acid tongue about everything from earmarks to aircraft carriers. But softer-spoken counterparts like Levin, Reed, or Nelson could take the edge off: McCaskill would sharpen it.