(CNN) President Donald Trump almost certainly won't get his "big bang" reopening of the frozen economy.

His hopes for a sharp rebound in the summer of his reelection year are likely to be dashed by the science of a virus that is highly contagious, for which there is no vaccine and no proven therapies.

Furthermore, many state governors and big city mayors — who so far retain more public trust over their management of the crisis than Trump — are nervous about a premature end to stay-at-home orders. Trump can't simply force them to open up.

And the administration itself appears far short of the readiness required to reopen the country safely. Mass testing capabilities needed to underwrite a staged return to normal life before the pandemic is contained are nowhere near needed levels.

There is also no sign of a government plan for how vital functions like air and surface transport can safely resume without triggering a new wave of mass infections.

Trump, however, appears increasingly keen to get everyone back to work, or at least is laying the groundwork to blame others if it can't happen, once again suggesting amid criticism of his leadership that states, and not Washington, should be in the lead.





One of the top US public health experts, Robert Redfield, who heads the US Centers for Disease Control and Prevention, appeared to endorse a gradual reopening. "Governors, get your states testing programs & apparatus perfected. Be ready, big things are happening. No excuses! The Federal Government is there to help. We are testing. More than any country in the World. Also, gear up with Face Masks!" the President tweeted on Sunday evening.One of the top US public health experts, Robert Redfield, who heads the US Centers for Disease Control and Prevention, appeared to endorse a gradual reopening.

"This pandemic has affected different parts of the country differently," Redfield said on NBC's "Today Show."

"We're looking at the data very carefully, county by county by county, and we will be assessing that," Redfield said. He added that before the US can start to get back to normal there needed to be greater capacity to identify, isolate and trace coronavirus cases through testing.

Trump also stoked fresh speculation about the standing of top health experts in his administration when he retweeted a call Sunday evening to fire Dr. Anthony Fauci, the government's top infectious disease specialist, who has publicly aired criticism of Trump's initial handling of the crisis.

No one says Trump's looming decision is easy. And heated debates are already occurring inside the administration over the issue. All public office holders must balance the devastating consequences of the government shutdown that threatens to trigger an economic depression with the need to stop a resurgence of the virus when hotspot areas pass their peak of infections.

But the lack of specifics so far -- even as Trump's target date of May 1 approaches -- will spark concern over whether a President who was negligent in recognizing the initial threat from the virus is up to presiding over the next critical stage in the fight.

The debate on reopening is heating up after the US passed 22,000 Covid-19-related deaths and at least half a million known cases. Not every country is testing the same way -- and there have been questions about whether every nation has been truthful -- but when it comes to the raw numbers, the US is currently the worst afflicted country in the world.

But there is increasing optimism that the rate of increase of infections is flattening and the US will fall short of the 100,000 to 240,000 deaths previously cited in models by the White House. Hopes that the death toll could be kept to the lower, but still very tragic, 60,000 range rest on the assumption that social distancing will remain in place through May.

In the days ahead, the President could be pulled one way by the advice of his top health advisers and in an opposite direction by economic aides conscious that the longer the lockdown goes on, the more likely it will be that jobs will permanently disappear. There are strong calls from conservative commentators who influence Trump for the economy to be unleashed.

Fauci: No flick of the switch

Fauci offered some qualified hope but also a warning on CNN's "State of the Union" on Sunday. He said it might be possible by the end of the month to judge whether some social-distancing measures could be eased.

"It's going to be depending where you are in the country, the nature of the outbreak that you have already experienced, and the threat of an outbreak that you may not have experienced," Fauci told Jake Tapper.

"It is not going to be a light switch that we say, OK, it is now June, July or whatever, click, the light switch goes back on," Fauci said.

Such a phased and limited initial opening appears likely to fall well short of the President's hopes for a swift economic rebound.

"It would be nice to be able to open with a big bang and open up our country, or certainly most of our country," Trump said last week. On Fox News on Saturday, he said the decision was the toughest of his life.

"There are a lot of things that go into a decision like that. It's going to be based on a lot of facts and a lot of instinct, also," the President said.

Trump's willingness to rely on instinct will trouble his critics, given his instinct to downplay the virus for weeks earlier this year.

JUST WATCHED Fauci: There was 'pushback' to February shutdown Replay More Videos ... MUST WATCH Fauci: There was 'pushback' to February shutdown 01:19

Fauci appeared to incur Trump's ire on "State of the Union" Sunday morning when he admitted that there had been "a lot of pushback" to calls inside the administration for earlier social distancing.

"I mean, obviously, you could logically say that if you had a process that was ongoing and you started mitigation earlier, you could have saved lives," Fauci said.

Hours later, Trump retweeted a user who said it was "Time to #FireFauci." The tweet suggested that Fauci mistakenly downplayed the initial threat of coronavirus to the US in late February when he said the "country as a whole ... still remains at low risk," though the infectious disease expert was referring specifically to an outbreak in Washington state and qualified that "this is an evolving situation."

Mass testing needed for American life to come back

Several think tanks and experts have released detailed plans for how to transition from the current state of shutdown to a reopening of shops, businesses, transport, sports events and large scale social gatherings.

They rely on a massive expansion of testing, contact tracing and isolation — possibly with cellphone apps that may allow some sectors of the population to begin returning to work.

But the administration has for weeks failed to deliver on the expansion of testing that would be required under such plans.

The President boasts each day of testing programs that have now reached 2 million Americans. But under most reopening plans, several million people per day may need to be tested to prevent a new spike in infections that could overwhelm hospitals.

Currently, there are insufficient diagnostic tests to cover all front-line health workers -- or many Americans who fall sick. And test results take days to come back in some cases.

Public health experts are also calling for a surge in serology blood-based testing that can identify antibodies in a patient's body developed to fight the disease, which could allow that person t o return to normal life.

"Do you need it? No. Is it a nice thing to do? Yes," Trump said. "We're talking about 325 million people and that's not going to happen."

Former Vice President Joe Biden is targeting the paucity of testing as he rolls out his own plan to tackle the virus while stepping up his general election campaign against Trump.

"We should be running multiple times the number of diagnostic tests we're performing right now," Biden wrote in a New York Times op-ed p ublished on Sunday.

"This isn't rocket science; it's about investment and execution. We are now several months into this crisis, and still this administration has not squarely faced up to the 'original sin' in its failed response — the failure to test."

Trump can't order the economy reopened

Owing to the US federal system, Trump can't simply order people back to work.

Governors and mayors who closed their jurisdictions down will make that choice.

"If we had better national strategies and universal testing and software-based contract tracing, then we could really figure out when opening makes sense and we could start to do that in the country," Lujan Grisham said.

New York Democratic Gov. Andrew Cuomo on Sunday acknowledged Americans want life back on track. But he warned that reopening must be adopted by adjacent states for it to work properly and to keep the virus under control.

"Nobody wants to pick between a public health strategy and an economic strategy. And as governor of the state, (I'm) not going to pick one over the other. We need a public health strategy that is safe, that is consistent with an economic strategy," Cuomo said.

Another local official in a similar position is Washington, DC, Mayor Muriel Bowser.

"We don't expect our peak medical surge to happen until June," Bowser said on CNN's "Inside Politics."

"And so we continue to look for ways, certainly, that we would be able to turn on our economy slowly. But I don't think that's going to be on May the 1st," Bowser said.

Still, in some areas of the nation that have been less afflicted by the virus than the big coastal conurbations, officials are hopeful that they can safely begin to move forward.

Arkansas Republican Gov. Asa Hutchinson defended his decision not to impose a statewide stay-at-home order Sunday on CNN's "State of the Union," arguing that the state's lack of population density meant that it was unnecessary.

"Right now, what we're doing proves to be successful, this targeted approach," Hutchinson said.

This story has been updated to include Trump's retweet calling for Fauci to be fired.