Explicit standards for evidence and argument are critical in a competitive system where competing groups have palpable incentives to withhold information, monger stilted information, use irrelevant information, or use any tactic to win.
Different branches of the US government use different epistemic standards.
The US judicial system uses the adversarial system in which each of the parties presents its case to a neutral party (judge or jury). Each side is supposed to furnish evidence in support of its argument, and an ‘impartial’ judge decides on what evidence is better in terms of its applicability and strength.
The adversarial system is a competitive system that relies on the sparring parties to furnish evidence. Like any competitive system, the sparring parties have incentives to withhold information from each other and misrepresent information. The system relies on the ‘other’ party to excavate any such violations, and sometimes on the neutral party. There are some other formal procedures to limit the kind of evidence that can be presented (though some are rooted in alternate theories) and procedures for sharing corroborative evidence. There are also formal procedures as to what kind of arguments can be presented.
The adversarial judicial process inarguably uses the strictest standards of evidence amongst any branch of government.
While the legislative process is largely a ‘competitive’ system, it has no formal epistemic standards limiting the kind of evidence or arguments that can be presented. The strength of the evidence presented, its applicability, etc. are either ‘judged’ by ‘citizens’ (substantially mediated by media) or by members of the other competing party.
The problem with legislative branch is not only that it is a competitive system, but that is a corrupt, special interest driven competitive system. The system provides little incentive to the members to judge the evidence impartially with the nation’s best interests in mind.
There are no epistemic standards that hold back the executive branch except for some loose constraints that tie those standards to the marketability of a particular policy decision.
Congress also uses the ‘Inquisitorial system’ when it conducts ‘Congressional Hearings’ to ‘investigate’ a particular issue. Of course, due to partisanship pressures, the inquisitorial system often uncomfortably borders on ‘inquisition’.
One way to correct the problem would be to create governance structures that explicitly involve independent bodies that judge the strength and applicability of evidence presented.