WASHINGTON — The White House is on a collision course with Catholic bishops in an intractable dispute over abortion that could blow up the fragile political coalition behind President Barack Obama’s health care overhaul.

A top Obama administration official on Thursday praised the new Senate health care bill’s attempt to find a compromise on abortion coverage — even as an official of the U.S. Conference of Catholic Bishops said Sen. Harry Reid’s bill is the worst he’s seen so far on the divisive issue.