There is nothing to Veto.
The Law giving the POTUS to power enact National Emergency measures was passed right after Nixon Resigned.
“The Law giving the POTUS to power enact National Emergency measures was passed right after Nixon Resigned.”
And he doesn’t even need that law to act. Article 2 and Article 4 section 4 gives him plenary authority and under Article 4, he is compelled to protect the states from invasion