The New York metro area has fast become the hardest-hit region in the U.S., as coronavirus cases skyrocket and hospitals warn they’re at risk of being overrun with cases.The governors of New York and New Jersey have already imposed strict social distancing restrictions, with federal officials urging those traveling out of the area to immediately self-isolate.

Trump’s proposal would be even more draconian, and effectively prohibit travel from New York, New Jersey or Connecticut to other states through what he termed “an enforceable quarantine.”

Yet that would accomplish little, health experts said, warning that the U.S. is well past trying to contain coronavirus to certain geographic regions — and should focus instead on identifying the next batch of hot spots.

“New York is further ahead on the path that the whole country is on,” said Jeremy Konyndyk, a senior policy fellow at the Center for Global Development and former Obama-era foreign aid official. “What we don’t need is inconsistent social distancing and quarantining policies that are driven by presidential tweet.”

Indeed, cases have begun to pile up in cities, including New Orleans, Chicago and Detroit. And given the time it typically takes for people to show symptoms, go to a doctor and receive their test results, public health experts said the official numbers could already be two to three weeks out of date.

It’s also unclear whether the Trump administration has authority to force quarantines on states without governors’ approval. Trump’s suggestion he might close off New York appeared to catch Gov. Andrew Cuomo by surprise.