The DC Circuit concludes that the President can never be forced to give info to Congress, but everything will be fine because the Constitution makes the President and Congress give an oath, and "those so bound have a duty to conduct themselves with fidelity to the Constitution."
The President can't be impeached for refusing to give info to Congress, because the House is required to first use the courts to force the President to give them info, and also Congress can't use the courts to force the President to give them info, because that's not allowed.🤷♀️
If this opinion stands, Trump should just order the Executive Branch to disregard federal court decisions he doesn't like. After all, interbranch disputes are a thorny business, so better to leave the courts out of resolving Trump's conflict with court rulings.
The Executive Branch is an independent branch of government. And it's supposed to just do whatever the federal courts tells it to? The very idea is an affront to the structure of our government, and its careful balance of competing constitutional interests.
The Sergeant at Arms should just go arrest McGahn, and also Bolton while he's at it, and hold them in a tiny cage until they testify. And if anyone tries to get the courts involved, the House needs to tell them, "Um, excuse me, this is an interbranch conflict here, so piss off."
"Congress doesn't need the courts' help to compel the Executive, they can just use appropriations and impeachment and do it themselves," says the DC Circuit about a President who did not produce a single document or witness while being impeached for disregarding appropriations. 
Luckily, Republicans have previously made it clear that they too believe Congress has the firmly established right to obtain whatever info it wants from the Executive Branch. *stares directly into the camera*
To be clear, even the two judges who ruled in Trump's favor agree that what Trump is doing is obstruction. They just think that's okay, because Trump swore an oath and is now bound to uphold the Constitution, so that'll stop him from doing anything that's too much of a problem.
The thing about the McGahn decision that gets me is that it's saying "so, for the past 2.5 centuries our Constitution has rested on the Executive and Legislative branches being locked into a game of chicken, and if one side calls the other's bluff this whole thing goes tits up."
