Back when this was onesy-twosy stuff this wasn’t considered such a grave matter.
Now that it is staggering the ability of the USA to assimilate, and openly warping the political process by being allowed a swaying hand in a major political party, it seems time to invoke a separate provision of the Constitution to “protect the states against invasion.”
I rather prefer the phrase, "Clear and present danger." I hope Trump uses it in his EO.