I'm no expert in legal-speak but I see this statement as follows:
The United States is required to protect the State of Washington (and all other states) if (let's say) Canada invades the state.
And, if the state legislature or the governor appeals to the federal government, then the United States is additionally required to act against domestic violence.
So, if the Governor wants Trumps to intervene, and makes a formal application, then it is a federal matter. But not before.
I disagree... but I’m not an expert, either. US citizens are having their constitutional rights trampled. There is no “republican form of government” in the occupied zone. The Federal government has ultimate authority under the Constitution in the protection of basic rights... otherwise, there is no rationale to having a Supreme Court. If the local and State authorities won’t protect their citizens, the Fed must.
Trump probably knows that the "domestic" thugs are backed in large part with foreign money (Soros? China?). That makes it a federal matter in my eyes.