SAN JUAN, P.R. — Moments after being sworn in as Puerto Rico’s new governor, Pedro R. Pierluisi pledged in no uncertain terms that he would willingly step down in the coming days if the island’s Senate voted against confirming him — even if that made him one of the shortest-serving governors ever to take office.

“I have to admit that that could happen,” Mr. Pierluisi said with a chuckle. “But that’s the situation.”

[Update: Supreme Court ousts Puerto Rico governor and another is sworn in.]

That was on Friday. By Sunday afternoon, Mr. Pierluisi had appeared to reverse himself, arguing that the Senate had no say and that the courts would settle the issue. Then a few hours later, he was sued.

Puerto Rico remained on Monday where it has been for weeks: in a state of protracted political paralysis that appears not to have been resolved by the installation of Mr. Pierluisi, who took over after former Gov. Ricardo A. Rosselló’s resignation became effective on Friday.