U.S., March 29 -- On the recommendation of the White House CoronaVirus Task Force, and upon consultation with the Governor's of New York, New Jersey and Connecticut, I have asked the CDC to issue a strong Travel Advisory, to be administered by the Governors, in consultation with the Federal Government. The quarantine will not be necessary.

The change of mind by President Trump was in response to New York's governor saying such a measure would be the Federal Government issuing a declaration of war against New York. It may be the start of a civil war.

Shortly after the presidents tweet the CDC issued the following press-release

Due to extensive community transmission of COVID -19 in the area, CDC urges residents of New York, New Jersey, ...