WASHINGTON — The voters of Utah and Idaho, two deeply Republican states, defied the will of their political leaders in November and voted to expand Medicaid under the Affordable Care Act. Now those leaders are striking back, moving to roll back the expansions — with encouragement, they say, from the Trump administration.

Utah’s ballot measure, approved with support from 53 percent of voters, would expand Medicaid to cover people with incomes up to 138 percent of the poverty level — up to about $16,750 a year for an individual — and pay the state’s share with a small increase of the sales tax. Under the ballot initiative, 150,000 people are expected to gain coverage, starting April 1.

In Idaho, more than 60 percent of voters supported a ballot measure to expand Medicaid.

But in both states, the Republican Legislatures are looking for ways to roll back those votes.

The bill barreling through the Utah Legislature was “an effort to override the will of the people,” said Matthew Slonaker, the executive director of the Utah Health Policy Project, a nonprofit group that supported the full expansion of Medicaid.