(CNN) President Donald Trump and top US health officials called on every American Monday to do their part to stop the spread of COVID-19.

It was a marked change from the previous day, when Trump said things were under control

This is not a setback or a difficulty for the economy to overcome. It's an all-out attack on our way of life by a microbe. This is Pearl Harbor. This is 9/11. But the enemy is totally invisible.

Patriotic duty -- In an odd twist on the idea of service, the government is asking people to do nothing. Stay out of restaurants and bars. Avoid gatherings of 10 or more for two weeks. The guidelines could be extended after that.

Millennials -- In particular, Dr. Deborah Birx, the coronavirus task force coordinator, -- In particular, Dr. Deborah Birx, the coronavirus task force coordinator, appealed to millennials , telling the largest current generation of Americans that they need to shield older generations more susceptible to the virus. "We now need to appeal to every single American so that they can have their role in stopping this virus," she said, before singling out millennials as the "core group who can stop this virus" by avoiding public contact.

A history of sacrifice -- Americans were called on to serve and work in the national interest when the country mobilized for the war effort in World War II.

Americans turned against service in Vietnam when the cost became too great. More recently, after 9/11, they were asked to go out and buy things to prop up a flailing economy.

They're not asked to do much anymore. But now, with a global pandemic threatening older Americans, fighting the enemy requires a collective isolation from generations that have social hard-wired into their DNA. "We've always heard about the Greatest Generation," Birx said. "We're protecting the Greatest Generation right now and the children of the Greatest Generation." (Yes, that would be the boomers, of which Birx is one.)

Recommendations, not mandates:

-- If you feel sick, stay home and call your doctor.

-- If you're older, stay home and away from people.

-- Stay away from bars, restaurants and food courts.

-- Avoid discretionary travel or social gatherings.

-- Avoid social gatherings in groups of 10 or more.

-- Close schools.

-- Cancel all social visits in homes.

-- Do not visit nursing homes or retirement communities.

State and local governments are taking an even harder line.

-- Louisiana is closing all bars, movie theaters and gyms until April 13.

-- DC is doing the same until April 1.

Not enough ventilators -- In a call with governors, Trump encouraged state leaders to try to get their own ventilators to treat an expected onslaught of sick older Americans.

Don't hoard groceries -- But he encouraged Americans not to stampede grocery stores and cause shortages of staples. The country's supply chain could be put at risk.

I can't keep up with all this. It's crazy town.

Not overreaction

Dr. Anthony Fauci, the nation's top infectious disease doctor, dismissed the idea that these new guidelines are over the top during the White House briefing

It will always seem that the best way to address it were to be doing something that looks like it might be an overreaction. It isn't an overreaction, it's a reaction that we feel is commensurate, what is actually going on in reality.

So take a look at the guidelines, read them carefully and we hope that the people of the United States will take them very seriously, because they will fail if people don't adhere to them. We have to have -- as a whole country -- cooperate and collaborate to make sure these get done.

Americans' well-being is at risk

It is not at all clear how the US economy will fare in the coming months.

Worst point drop in history -- Markets plummeted to start Monday and then dropped as Trump suggested the outbreak could last until July or August. Almost all of the market gains during Trump's presidency are gone.

Let me write that again:

More than half of US jobs are at risk.

From Isidore's story:

Nearly 80 million jobs in the US economy are at high or moderate risk today, according to analysis in the last week from Moody's Analytics. That's more than half of the 153 million jobs in the economy overall.

That doesn't mean that all those jobs will be lost. But it's probable that as many as 10 million of those workers could see some impact to their paychecks -- either layoffs, furloughs, fewer hours or wage cuts, said Mark Zandi, chief economist at Moody's Analytics.

Of those 80 million jobs, Moody's Analytics projects that 27 million are at high risk due to the virus, primarily in transportation and travel, leisure and hospitality, temporary help services, and oil drilling and extraction. Maybe 20% of those workers, comprising about 5 million jobs, will be affected, Zandi said.

A first stimulus bill -- certainly there will have to be more -- has not yet passed through the Senate despite backing from the White House.

Already, lawmakers are looking forward to what might come next.

There's a fear the entire airline industry could fold. Should taxpayers prop it up? Airports have already asked for $10 billion.

$1,000 for every American? -- Sen. Mitt Romney, a Utah Republican, backed an almost Andrew Yang-style proposal for every American to get a $1,000 payment. Former Democratic presidential candidate Yang backed a monthly $1,000 dividend for Americans. Romney is backing a one-time payment. (Reminder: George W. Bush sent out -- Sen. Mitt Romney, a Utah Republican, backed an almost Andrew Yang-style proposal for every American to get a $1,000 payment. Former Democratic presidential candidate Yang backed a monthly $1,000 dividend for Americans. Romney is backing a one-time payment. (Reminder: George W. Bush sent out two rounds of rebate checks during his time in office. Can you still remember what you did with yours?)

What are we doing here?

The American system of government has been challenged to deal with a singular President and a divided country that will decide whether he should get another four years in the White House.