AT lunch a few weeks ago, State Senator John McKinney spotted State Representative Michael P. Lawlor approaching a bank of polished brass elevators in the Legislative Office Building, his smile widening as Mr. Lawlor drew close. “Thank you for getting me every Catholic vote in the Fourth Congressional District,” teased Mr. McKinney, a Republican from Fairfield who is Episcopalian. Mr. Lawlor, a Democrat from East Haven who is Catholic, had little choice but to glumly tolerate the gibe from Mr. McKinney, the Senate minority leader. After years of deftly threading his way through a thicket of social issues as co-chairman of the General Assembly’s judiciary committee, Mr. Lawlor had stumbled into a religious war. And he blamed himself.