Their take on that would be to declare that SCOTUS-restricting law as unconstitutional.
Article III--In all Cases affecting Ambassadors, other public Ministers and Consuls, and those in which a State shall be Party, the supreme Court shall have original jurisdiction. In all the other Cases before mentioned, the Supreme Court shall have appellate Jurisdiction, both as to Law and Fact, with such Exceptions, and under such Regulations as the Congress shall make.
Of course they could try to ignore it. That's why you put criminal penalties for usurpation of power if the justices if they try to rule on it anyway.