WASHINGTON — A federal appeals court, in a far-reaching decision that could cripple operations at two agencies, sharply limited the president’s power to bypass Senate confirmation.

The broader implications of the ruling mean the Senate’s Republican minority can all but halt the work of the new Consumer Financial Protection Bureau and the NLRB by preventing the president from appointing its leaders or board members.

The decision also leaves in doubt the legal status of regulations and enforcement actions made by those agencies in the last year.

The panel for the U.S. Court of Appeals for the District of Columbia ruled that “recess appointments” can be made by the president only when Congress has formally adjourned, not when lawmakers leave Washington for a break that lasts a few days or a few weeks.

The Senate has recently held brief “pro forma” sessions when members are away, and the appeals court agreed with Senate Republicans that these breaks do not count as a recess.

The Constitution’s check on presidential appointments would be “turned upside down if the president could make appointments any time the Senate so much as broke for lunch,” said Chief Judge David B. Sentelle.

Obama’s lawyers are almost certain to appeal to the Supreme Court. White House press secretary Jay Carney called Friday’s decision “novel and unprecedented. It contradicts 150 years of practice by Democratic and Republican administrations.”

Republicans and some business lawyers were jubilant, calling the decision a vital check on presidential power.

The decision is “good news for checks and balances, an essential factor in our system of government that safeguards ‘we the people’ against unchecked power,” said Sen. Charles E. Grassley, R-Iowa.

Union officials and liberal advocates said the decision enables a conservative minority in the Senate to block the work of agencies set up to protect consumers and to enforce the laws that protect a worker’s right to join a union.

AFL-CIO President Richard Trumka called the decision “radical” and “shocking,” noting that all three judges were Republican appointees.

At the same time he made the NLRB appointments, Obama nominated Richard Cordray to head the Consumer Financial Protection Bureau, an agency overseeing the financial industry to police any abuses by Wall Street and big banks.

Since Obama’s recess appointment of Cordray as the bureau’s first director, the agency has been very active. It has issued sweeping new rules for mortgages, begun overseeing large credit-reporting and debt-collection companies and required mortgage servicers to take steps to help keep delinquent borrowers in their homes.