WASHINGTON — When President Obama relied heavily on executive orders to push through policies that had no chance in Congress, Republicans called him a dictator who abused his power and disregarded the Constitution. They even took him to court.

“We have an increasingly lawless presidency where he is actually doing the job of Congress, writing new policies and laws without going through Congress,” Representative Paul D. Ryan, then the Budget Committee chairman, said in a 2014 television interview after Mr. Obama made clear in his State of the Union address that he would readily take unilateral action to get his way.

Now President Trump, at the start of his tenure, is relying heavily on executive actions not just to reverse Obama administration initiatives, but to enact new federal policies covering immigration, health care and other areas in ways that could be seen more as the province of the House and Senate. And he is doing that with clear Republican majorities in Congress.

The flurry of administration edicts flowing from the Trump White House puts some top Republicans in the awkward position of welcoming aggressive executive muscle flexing from a president of their own party after castigating Mr. Obama for using the same approach.