Update: President Trump declared a state of emergency Friday afternoon.

As the global financial system teetered on the brink in the fall of 2008, a Republican president and congressional Democrats, recognizing the severity of the crisis, worked together to pass a bailout package for the financial industry that despite its many flaws and compromises helped to prevent a second Great Depression.

The coronavirus pandemic poses a different kind of challenge, threatening the nation’s health as well as its economic prosperity, but it must be met with the same kind of audacious, coherent and coordinated response.

So far, as the virus spreads from person to person and state to state, the federal government has lagged several steps behind. While President Trump on Wednesday night finally began to acknowledge the seriousness of a threat that he has repeatedly played down, he mustered the determination only to belatedly slam yet another barn door, banning travel from Europe too late to significantly retard the spread of a virus that is already endemic to the United States.

Americans need much more from Mr. Trump. The president must try to emulate the sober urgency with which his immediate predecessors, President George W. Bush and President Barack Obama, confronted the 2008 crisis. Mr. Trump needs to grasp that the best way to slow the spread of the virus and to minimize long-term economic damage is to make the difficult but necessary decision to put the economy on ice, as leaders are doing in other nations beset by the virus. That means emptying theater halls and stadiums, paying sick workers to stay home, closing schools and universities — in short, bringing much of normal life, including economic life, to a standstill.