|So much for hiring only "the best"|
A federal judge dismissed Trump's claims that Congress cannot demand information about his finances because there was no "legislative purpose" for the investigation. As the judge properly pointed out, Congress has ALWAYS had the right to investigate without "legislative purpose". Article 1, Section 8 lists what Congress can do to oversee the government aside from legislation. What the judge told Trump's lawyers was that they didn't have a viable argument to try to redefine what powers Congress has, that precedent since the Constitution was ratified has shown that Congress has always had the oversight they are challenging, and he also refused to grant a stay while they appealed his decision.
They will appeal, of course, but most legal experts say that they don't have a prayer - you cannot make the argument that Congress can only do things that have a "legislative purpose", because that's not what the Constitution says. Which Trump and his lawyers would know if they bothered to actually READ the Constitution.
Three co-equal branches of government, Checks and balances. The Executive branch does not get to decide what the other branches can and cannot do. The President s not the boss.