WASHINGTON — President Donald Trump is increasingly intervening in the economy, making decisions about corporate winners and losers in ways that Republicans for decades have insisted should be left to free markets — not the government.

The shift amounts to a major change in the GOP’s approach to the management of the economy, and promises to shape the success of everything from American agriculture and manufacturing to the companies that produce the nation’s electricity.

Last week, citing national security, Trump ordered the Energy Department to compel power-grid operators to buy from ailing coal and nuclear plants that otherwise would be forced to shut down because of competition from cheaper sources.

The order came one day after the president imposed historic metals tariffs on some of the country’s strongest allies and trading partners. Now the Commerce Department is further picking winners and losers as it weighs thousands of requests from companies for waivers from the import taxes.

“It replaces the invisible hand with the government hand,” said Mary Lovely, a Syracuse University economist. “You’re replacing the market with government fiat.”

The president has chastised individual companies, second-guessed the U.S. Postal Service’s business arrangement with Amazon and put pressure on Boeing and Lockheed about the cost of their products.

Trump’s order to Energy Secretary Rick Perry to stop the shutdown of coal and nuclear plants is the latest example of government intervention. The method will probably resemble a 41-page memo discussed this week by the National Security Council and at the Cabinet deputies-level meeting.

According to the memo, the Energy Department should invoke emergency authority under Cold War legislation — the Defense Production Act of 1950 and the Federal Power Act — to require regional electricity grids to purchase electric power from a list of plants chosen by the department. The memo said the criteria would be reliability, a quality that is the subject of hot debate.

The activist group Earthjustice issued a statement titled “Trump Administration Resorts to Soviet-style Takeover of Private Energy Markets To Keep Dirty, Uneconomic Coal Plants Running.” Staff attorney Kim Smaczniak said “no law gives the administration the power to set energy prices.”

The companies running regional electricity grids operate under a competitive bidding process that has won praise from environmental groups, utilities and regulators.

Those regulators, the independent Federal Energy Regulatory Commission, rejected a similar Energy Department rescue for coal and nuclear plants in January.

But utility industry executives now worry that Trump is insisting on forcing through a plan akin to the one already rejected by regulators because of political rather than economic concerns.

Industry experts expect that the Appalachian coal mining firm Murray Energy and the Ohio-based utility FirstEnergy — which first broached the idea of a rescue plan to Perry last year — will be near the top of the list of companies benefiting from Trump’s order.

Murray chief executive Robert Murray and FirstEnergy chief executive Charles Jones Sr. have contributed heavily to Trump and GOP political activities.

Murray presented an emergency plan to Perry in March 2017, days after Perry became Energy secretary. Murray and Jones met Trump together in August 2017 to appeal for aid to prevent a FirstEnergy subsidiary from filing for bankruptcy, which it did anyway in early April. FirstEnergy’s highly paid lobbyist, Jeff Miller, was Perry’s campaign manager, and Trump dined with him and a small number of other reelection strategists that week.

Of course, Trump isn’t the only one to tinker with market forces. President Barack Obama backed subsidies for wind and solar. And about 30 states have adopted laws mandating minimum purchases of renewable energy.

Obama also won passage of a health care reform package that created winners and losers. Republicans criticized the Affordable Care Act at the time for forcing people to make purchases through the individual mandate.

Now Trump’s economic assertiveness is beginning to draw a response from congressional Republicans. On Friday, in the wake of the announcement on steel tariffs, Sen. Patrick Toomey, R-Pa., said that he and Sen. Mike Lee, R-Utah, would co-sponsor legislation “to rein in the executive branch’s power to impose unilateral tax increases like these.”

Toomey, who said the import taxes would hurt American workers and employers, tweeted: “Congress should assert its constitutional responsibility and lead on trade policy so Americans keep access to affordable goods and services, and the opportunity to sell our products abroad.”

The implementation of the tariffs illustrates how Trump’s interventionist impulses are creating a cumbersome, bureaucratic process with Washington sitting in the middle.

In March, when the president announced plans to impose tariffs of 25 percent on steel and 10 percent on aluminum, he allowed companies to petition the Commerce Department for waivers.

The department said it would allow companies to escape the tariffs if they relied upon foreign suppliers for steel or aluminum products that were unavailable in the United States in “satisfactory quality or in a sufficient and reasonably available amount.”

While the department promised decisions within 90 days, the process has bogged down amid several thousand applications for relief.