WASHINGTON — President Trump said on Wednesday night that he was “strongly considering” commuting the 14-year prison sentence of Rod R. Blagojevich, the former Illinois governor who was convicted of trying to essentially sell President Barack Obama’s vacated Senate seat for personal gain.

But after a day of pushback from conservatives and the Illinois delegation of House Republicans, Mr. Trump was having second thoughts, people close to him said. On Thursday night, he said on Twitter that the matter was simply being reviewed.

White House officials had said the move could come as early as this week, but the president began to face mounting blowback given that Mr. Blagojevich’s crime has long been seen as the epitome of the kind of pay-to-play that Mr. Trump has claimed he wanted to stop when he took office.

[Who is Rod Blagojevich and how does he know President Trump?]

Mr. Trump disclosed his initial plans aboard Air Force One on Wednesday after a day of highly critical news coverage that focused on the reception toward the president as he traveled to the sites of mass shootings in El Paso and Dayton, Ohio, that left 31 dead.