The Constitution says foreign policy is the domain of the federal government.
The coronavirus response is the responsibility of the individual states
Not quite as simple as what you have stated, but your statement is largely correct with exceptions.
Who Calls the Shots During a Pandemic, the U.S. Government or States? Q&A with RAND Experts
It needs to be a combination. The federal government and the states have different proficiencies and different powers they can bring to bear that are relevant to this crisis.
The federal government should be taking a lead in terms of any interstate travel, or virus-spread risks, and they do have power to do that. The CDC has quarantine power (under Title 42), for example. Also, in terms of coordinating supplies, personal protective equipment, ventilators, those sorts of things, that's a federal jurisdictional area, so we don't have states competing.
In terms of economic stimulus, as we've seen, that's a federal response because states don't have the funds to be dealing with this.
Sadly, the virus doesn't respect state lines. Looking at parallel situations, there are federal activities like
FEMA funding for state responses and National Guard deployments. There is cooperation around ports of entry, where there's a necessary working relationship between the
Coast Guard, Customs & Border Protection, and local law enforcement.
Intelligence and public health surveillance resides at the federal level.
So, to reemphasize what was stated earlier,
it needs to be a combination. What is needed is a brain trust. The idea is that expertise is easily identified in a central place in a way that can be pushed out to all communities across the country, with guidelines that are consistent with evidence. That was quite helpful, for example, with Zika, from CDC. And
NETEC, a network that was set up for Ebola, with expertise concentrated in New York at Bellevue, in Atlanta at Emory, and in Nebraska.
Those experts were able to share protocols about how to treat patients. They set up a central institutional review board, so that research could be instituted quickly and in real time.
We can see lessons learned from other countries. Taiwan and South Korea have had much more aggressive physical distancing measures and contact tracing. Early evidence suggests these things seem to work when centrally coordinated. If the federal government uses its leverage to do things that are evidence-based, and in accordance with sound advice from the CDC and others, it should work well.