WASHINGTON — Under intense bipartisan pressure, President Trump on Sunday signed a sweeping coronavirus relief and spending bill — the denouement of a days-long drama over whether he would allow millions of Americans to endure a devastating cut to unemployment benefits and force a chaotic shutdown of the federal government in the final weeks of his administration.

The abrupt reversal by the president, ensconced at his Florida resort, came as converging crises of COVID-19, economic suffering, the looming government shutdown and Trump’s ongoing fight to overturn the election drew expressions of alarm from lawmakers. One Republican senator voiced worry earlier in the day that the departing president could leave a legacy of “chaos, misery and erratic behavior” if he failed to sign the measure.

In a White House statement announcing his action, Trump said it was his “responsibility to protect the people of our country from the economic devastation and hardship that was caused by” the coronavirus. He clearly signed the bill grudgingly, saying he would send a “redlined” version to Congress seeking the removal of some spending from the legislation.

The measure renews enhanced jobless benefits that have been a lifeline for those thrown out of work by the still-raging pandemic, and provides funding for distributing the COVID-19 vaccines. It also keeps the government afloat for the rest of the fiscal year, which ends in September,averting what otherwise would have been a shutdown starting Tuesday.