WASHINGTON — Hospital leaders, stung by the passage of a law that will cut nearly $1 trillion in Medicaid funding over the next decade, have been racing to remake their systems.

And in Washington, some are building a long-shot plan to turn back the clock.

Hospital lobbyists and leaders have begun laying the groundwork to delay, roll back, or mitigate the unwelcome health care spending cuts used to help fund President Trump’s tax cut bill, according to four people familiar with the efforts.

“They see an opening,” said one lobbyist hired by hospital systems of their clients. “I don’t know if I do.”

It’s a difficult target, with a potentially lengthy timeline. The cuts were passed as part of President Trump’s signature tax cut law, and even potential Democratic majorities would have to win the president’s approval to change them. It would also mean coming up with substantial money to pay for the changes — and possibly finding a handful of Republican lawmakers who are willing to undo one of their landmark legislative achievements.