With President Trump’s promise to repeal and replace the Affordable Care Act nearly dead, administration officials are scaling back their ambitions to cut the corporate tax rate sharply, apparently taking a more pragmatic approach as they scramble to secure a major legislative victory this year.

In recent days, discussions among Mr. Trump’s economic advisers over promised tax cuts for corporations and individuals have taken on new urgency, a person who has been briefed on the matter said. One crucial point of discussions in the coming days, the person said, will be the proposed business tax rate. In April, a White House policy paper pegged it at 15 percent for corporations and small businesses alike. The current rate is 35 percent.