There is no court order requiring Marty to go to DC. Congress is nott a court. There also is no "production" re: Congress as Congress is nott a party to a lawsuit naming Marty in which evidence production would be relevant.
CONgress could GO to a court and ASK them for a court order. Butt CONgress itself cannot issue a court order.
CONgressional subpoena is NOTT a court ordered subpoena.
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