“Will the Supreme Court state the following: Congress makes its own rules or something like this is a Legislative branch issue?”
With respect to the rules and internal conduct of the House and the Senate the Supreme Court has traditionally deferred to the separation of powers provisions of the Constitution. Therefore it is unlikely to take up a case on the merits of the rules or the conduct of the Jan 6 committee.
Note it was not Congress convicting him for declining to testify. Congress referred his failure to honor the subpoena to the DOJ which in turn elected to prosecute him on the existing laws related to defying a congressional subpoena. He was convicted in a federal court of breaking a federal law.
If asked to rule on conduct of the trial in federal court, and/or the statute he was convicted of violating, the Supreme Court will likely uphold the law and the conviction. Almost any judge will agree Bannon should have followed the law and appeared to testify when served with a lawful subpoena. He had the option when appearing before the committee of pleading the 5th amendment and by exercising his constitutional rights not giving testimony. Recall the IRS official Lois Lerner took this approach when called to testify before a House committee in 2013. She did appear before a House committee but exercised her 5th amendment right not to answer questions put before her. Subsequently the House of Representatives voted her in contempt of Congress for not testifying, but she was not prosecuted by the DOJ because she did appear before the committee and invoked her 5th amendment rights. Had Bannon appeared before the January 6 committee, invoked his 5th amendment right not to testify against himself, and was then tried and convicted in federal court for not giving testimony, it is very possible the Supreme Court would have overturned the conviction on the grounds the Constitution specifically protects citizens from being compelled to testify against themselves.
Note the administration of the law is not always fair and those administering the legal process (law enforcement officials, judges, prosecutors) have considerable administrative discretion in determining who to prosecute and on what charges. We the people elected the Congressional representatives who conducted the January 6 inquiry. If they behaved poorly and unfairly, the remedy is for the people to vote them out of office as was done with Liz Cheney. As to the political weaponization of the DOJ, again the redress lies with the people to vote into office a new POTUS who will appoint an Attorney General who has respect for the law and will exercise appropriate judicial restraint. Alternatively, if the DOJ is abusing its power, Congress can impeach and remove from office the Attorney General or the President.
Our system of government only works if honorable people are elected and appointed to office who respect the Constitution and laws of the republic. Unfortunately, many citizens and elected representatives today are not virtuous nor do we as a nation today have a common sense of values. When the people and their government are corrupt, the results are predictable.
Bannon will likely serve a sentence and pay a fine for the choice he made to defy the subpoena.
“Almost any judge will agree Bannon should have followed the law and appeared to testify when served with a lawful subpoena.”
Bannon’s contention is that it was not a lawful subpoena. Plenty of legal experts also say that.
Where in the Constitution is the legislative branch granted the power to compel private citizens to testify before them?
The committee was formed in contravention of the house-established rules for forming it. Hence, any subpoena issued from the committee is not lawful.
The legitimacy of the committee is central to the lawfulness of the subpoena.
That's what they claim. I'm not sure the elections were legal.
Note the administration of the law is not always fair and those administering the legal process (law enforcement officials, judges, prosecutors) have considerable administrative discretion in determining who to prosecute and on what charges.Selective enforcement of the law by some states and the federal government has gone well past "discretion" and is now arbitrary. Near impossible to prove in court, but its happening in fact.