They point to the House GOP’s reluctance to bring an immigration bill to the floor, and to repeated efforts to overturn Obamacare and the president’s environmental policies.
Those last two moves have left Mr. Obama to act on his own.
On Thursday, he issued a memo to the heads of all federal departments and agencies telling them that by 2020, 20 percent of the energy they use must come from renewable resources such as wind or solar. That is more than twice the current rate.
On health care, Mr. Obama has made numerous interpretations that seem to conflict with his own law, including unilaterally suspending the employer mandate, deciding Americans can get subsidies even if they aren’t in state-run health care exchanges, and most recently ruling that states still could approve insurance plans even if they violate the law.
Administration officials said that last move relied on prosecutorial discretion — the same authority the president cited for halting deportations of Dreamers.
Presidents argue that they are allowed to interpret the laws, and President George W. Bush regularly issued signing statements laying out how he saw the laws Congress passed.
Mr. Obama criticized that practice and hasn’t issued anywhere near the number of signing statements, but analysts said he is still stretching the limits of his power by usurping Congress and the courts.
“The problem of what the president is doing is that he is not simply posing a danger to the constitutional system; he is becoming the very danger the Constitution was designed to avoid: that is, the concentration of power in any single branch,” said Jonathan Turley, a law professor at George Washington University, testifying about executive powers to the House Judiciary Committee this week.
“We’ve had the radical expansion of presidential powers under both President Bush and President Obama. We have what many once called an imperial presidency model of largely unchecked authority,” Mr. Turley said. “And with that trend, we also have the continued rise of this fourth branch. We have agencies that are now quite large that issue regulations.”
Nowhere is the fight more acute than on immigration, where activists have taken to blocking detention facilities and chaining themselves to buses to try to halt deportations.
Mr. Obama has carved nearly 500,000 Dreamers out of deportation, but the activists want a broader halt — at least to include the parents of the Dreamers.
Rep. Raul M. Grijalva, the Arizona Democrat who led Thursday’s rally outside the Capitol, said while it’s probably true the president can’t halt all deportations, he can take some more steps, such as not applying the full 10-year bar of admission to those who enter the country illegally.
“He’s probably legally correct saying, ‘I can’t do that, are you crazy?’ But OK, what are the options?” he said. “The first time we approached him on the Dreamers: ‘No, can’t do that, I don’t have the power.’ We think there are options that do extend the power.”