To the casual observer, the Obama administration’s approach to the congressional debate over patent trolls may seem erratic.

The White House has formally endorsed a House-passed bill (HR 3309) that would crack down on trolls by overhauling the rules of the civil litigation system — a bipartisan proposal that was declared dead on arrival in the Senate by Democrats who said it encroached on the judiciary’s turf and could inadvertently punish legitimate inventors who might be mischaracterized as bad actors.

The administration has also openly supported a competing Senate bill (S 1720) that would address trolls through narrower steps such as bolstering the Federal Trade Commission’s enforcement authority. Gene Sperling, the head of the president’s National Economic Council, has lauded by the bill by Judiciary Chairman Patrick J. Leahy, D-Vt., and Sen. Mike Lee, R-Utah, as a “big step in the right direction,” even though some Republicans argue that it doesn’t go far enough.

A third proposal (S 866), by Sen. Charles E. Schumer, D-N.Y., also enjoys White House backing, even though it is seen as a nonstarter by Leahy and was removed from the House proposal by Judiciary Chairman Robert W. Goodlatte, R-Va., because it was too controversial. The plan seeks to address patent trolls by giving defendants in infringement cases an opportunity to challenge patents after they have been granted.

Schumer and other supporters say it would get at the root of the patent troll problem by giving defendants in infringement cases an alternative to costly litigation, but critics say the idea could burden legitimate patent holders by subjecting them to uncertainty about whether their patents should have been granted in the first place.

The Commerce Department, which has led the administration’s push for a patent litigation overhaul, defended the White House’s positioning and said its priorities are not inconsistent. The deputy director of the Patent and Trademark Office, Michelle K. Lee, reiterated that theme in a March 25 speech to the IPO Education Foundation in which she said the administration and Congress are largely on the same page.

“Our active engagement with the House and Senate on their patent reform efforts is focused on three areas — increasing transparency, helping Main Street technology users and streamlining patent litigation costs,” Lee said, adding that “the key in all of these areas is striking the right balance.”