Unless they were lying this whole time?

10 U.S.C. §12406. National Guard in Federal service:

Whenever—
(1) the United States, or any of the Commonwealths
or possessions, is invaded or is in danger of invasion
by a foreign nation;
(2) there is a rebellion or danger of a rebellion against
the authority of the Government of the United States;
or
(3) the President is unable with the regular forces to
execute the laws of the United States;

the President may call into Federal service members
and units of the National Guard of any State in such
numbers as he considers necessary to repel the
invasion, suppress the rebellion, or execute those
laws. ***Orders for these purposes shall be issued
through the governors of the States*** or, in the case
of the District of Columbia, through the commanding
general of the National Guard of the District of
Columbia.

I think California already has a lawsuit against the deployment, so we'll see how long the NG is actually deployed.