– A federal government plan to combat the coronavirus warned policymakers last week that a pandemic “will last 18 months or longer” and could include “multiple waves,” resulting in widespread shortages that would strain consumers and the nation’s health care system.

The 100-page plan, dated Friday, the same day President Donald Trump declared a national emergency, laid out a grim prognosis for the spread of the virus and outlined a response that would activate agencies across the government and potentially employ special presidential powers to mobilize the private sector.

Among the “additional key federal decisions” listed among the options for Trump was invoking the Defense Production Act of 1950, a Korean War-era law that authorizes a president to take extraordinary action to force American industry to ramp up production of critical equipment and supplies such as ventilators, respirators and protective gear for health care workers.

“Shortages of products may occur, impacting health care, emergency services, and other elements of critical infrastructure,” the plan warned. “This includes potentially critical shortages of diagnostics, medical supplies (including PPE and pharmaceuticals), and staffing in some locations.” PPE refers to personal protective equipment.

The plan continued: “State and local governments, as well as critical infrastructure and communications channels, will be stressed and potentially less reliable. These stresses may also increase the challenges of getting updated messages and coordinating guidance to these jurisdictions directly.”

The plan, which was unclassified but marked “For Official Use Only // Not For Public Distribution or Release,” was shared with the New York Times as Trump escalated his efforts to curb the spread of the virus.

After weeks of playing down the seriousness of the pandemic, saying it would miraculously disappear, Trump began shifting to a more sober tone during a news conference Friday announcing the national emergency.

Much of the plan is bureaucratic in nature, describing coordination among agencies and actions that in some cases have already been taken, like urging schools to close and large events to be canceled. But its discussion of the Defense Production Act came as lawmakers and others urged Trump to invoke its powers, which he did on Wednesday.

“While the administration’s response has so far lacked the urgency this crisis has called for, there are still steps you can take to mitigate the damage,” Sen. Bob Menendez, D-N.J., wrote in a letter to Trump on Tuesday. “Invoking the powers vested in the DPA will enable the federal government to step up and take the type of aggressive steps needed in this time of uncertainty.”

Another letter sent last week by 57 House Democrats led by Rep. Andy Levin of Michigan made similar points: “We know what the demands of this time are, and we must act now to meet these demands.”

Sen. Jack Reed, D-R.I., said that Defense Secretary Mark Esper told him on Tuesday that the Pentagon would provide federal health workers with 5 million respirator masks and 2,000 specialized ventilators.

“The American public is on wartime footing in terms of battling the spread of this disease, and the Pentagon has to be part of the effort to help protect the health and safety of the American people,” Reed said.

Passed in 1950 shortly after U.S. troops went to war defending South Korea against an invasion from North Korea, the Defense Production Act authorized the president to require businesses to prioritize and accept contracts necessary for national defense. Over the years, its scope has been expanded.

“The spread and severity of COVID-19 will be difficult to forecast and characterize,” the government plan said. It warned of “significant shortages for government, private sector, and individual U.S. consumers.”