With Obama facing a potential rebuke from Republicans in the House for not seeking Congressional authorization for the Libya operation, some supporters of the operation are falling back on the “isolationist” canard.

Senators John McCain and Lindsey Graham have accused their colleagues in Congress of succumbing to “isolationism” in opposing operations in Libya, while the ranking House Democrat on the Armed Services Committee, Rep. Adam Smith, said that he was “concerned about the isolationist streak we’re seeing.”

There are plenty of reasons to oppose the intervention in Libya that don’t amount to isolationism, from a lack of clear strategic objectives or the capability to carry them through, to concern about the process by which the operations were authorized, to simply believing that U.S. armed forces are already overextended. As Jason Linkins noted the other day, “back in the day, we used to define `isolationism’ as a policy of total withdrawal from foreign entanglements, up to and including power alliances and trade agreements.” Linkins added that calling someone an “isolationist” because they oppose operations in Libya is like “calling someone who wants to cut Chateaubriand out of their diet a vegan.”

That’s exactly right. It’s silly to make that kind of accusation based on a single data point. It also has the obligations here backwards. It was the responsibility of those who supported intervening in Libya to make the case for doing so, and judging by the polls, they haven’t.

Plenty of smart people, like Marc Lynch, have substantively defended the decision to intervene in Libya. But resorting to the use of the “isolationism” slur against the operation’s critics is really just a sign of desperation. Those who support the operation are seeking to shift the onus for justifying their position on to those who oppose it, having failed to make a case themselves for intervening on the merits.