Art I, Section 30. Treasonattaindercorruption of blood and forfeituresestate of suicidesdeath by casualty.They can say that the actions of the Federal Government disregarding its sovereignty makes it an enemy, and that its operations to continually undermine the State's sovereignty are rendering aid and comfort to the state's enemies. Then they could deny the validity of federal jurisdiction claiming a conflict of interest.
That treason against the state can consist only in levying war against it, or in adhering to its enemies, giving them aid and comfort; that no person can be convicted of treason, unless on the testimony of two witnesses to the same overt act, or on his confession in open court; that no person can be attainted of treason or felony by the general assembly; that no conviction can work corruption of blood or forfeiture of estate; that the estates of such persons as may destroy their own lives shall descend or vest as in cases of natural death; and when any person shall be killed by casualty, there shall be no forfeiture by reason thereof.
Or if you want to invoke the federal judicial system, take this portion of CAPERTON v. A. T. MASSEY COAL CO.:
The second instance emerged in the criminal contempt context, where a judge had no pecuniary interest in the case but had determined in an earlier proceeding whether criminal charges should be brought and then proceeded to try and convict the petitioners. In re Murchison, 349 U. S. 133 . Finding that no man can be a judge in his own case, and no man is permitted to try cases where he has an interest in the outcome, id., at 136, the Court noted that the circumstances of the case and the prior relationship required recusal.
A federal agent or official charged with a state crime (or sued in a state court) for something they did in the course of their federal employment has an absolute right to be tried in federal court. Once they file the removal notice, the state court loses all jurisdiction. If the state court doesn't recognize that, federal marshals will come to see the state judge and set him straight. If the state resists them, the President will federalize the state's National Guard. This happened in the desegregation days when state courts refused to follow state court orders.
Or if you want to invoke the federal judicial system, take this portion of CAPERTON v. A. T. MASSEY COAL CO.
Caperton was talking about an individual judge being biased, not about the entire federal government.