The CRS is Congress's own research arm. Its analysts write briefings for members of both parties, which means the reports are deliberately non-partisan and assume no prior expertise. They are usually the single best starting point on any federal policy question.
A typical report explains the background of an issue, the current law, the main policy options and the arguments made for each. Every report is now published free at crsreports.congress.gov. One caution: reports are updated at irregular intervals, so the date of issuance matters more than the year on the cover.
When a bill has a cost, the CBO estimates it. Those estimates are the source of most of the dollar figures quoted in budget arguments, and they are frequently quoted without the assumptions that produced them.
A CBO score states what it assumed, over what window, and how uncertain the estimate is. Reading the assumptions is usually more informative than the headline number, because that is where two sides of a budget argument are actually disagreeing.
The GAO investigates whether federal programmes work. Its reports are unusually readable for audit documents, and each opens with a plain summary of what was found and what the agency was told to do about it.
If an argument turns on whether a programme is effective or wasteful, a GAO report is often the only rigorous evidence available, and it will usually be more equivocal than either side's summary of it.
Most policy that affects people directly is made through regulation rather than legislation. The Federal Register is the daily record of that process: proposed rules, final rules, and the agency's own explanation of its reasoning.
Regulations.gov carries the public comments filed on each proposal. Those comments are where industry groups, advocacy organisations and individuals state their case in detail, and they are a useful corrective to press coverage that quotes only the loudest party.
Most contested economic numbers trace back to a handful of agencies. The Bureau of Labor Statistics publishes employment, wages and inflation. The Census Bureau covers population, income and poverty. The Bureau of Economic Analysis produces GDP and trade figures.
Each publishes its methodology alongside its data, which is how you discover that two people citing different unemployment figures may both be accurate and simply using different definitions. The headline unemployment rate excludes people who have stopped looking for work; a broader measure published in the same release includes them. Neither figure is wrong, and an argument conducted without naming which one is being used cannot be resolved.
The same pattern recurs across almost every disputed statistic. Poverty, inflation, immigration enforcement and gun deaths all have more than one official measure, each defined for a different purpose. Finding out which definition a claim rests on usually explains the disagreement faster than arguing about the number.
Court filings. When a policy is challenged, the filings become public, and they are often the clearest statement of each side's case that exists anywhere. Briefs are written to persuade a judge rather than a voter, which tends to make them more precise and better sourced than the public argument. CourtListener carries federal opinions and dockets free of charge, and Supreme Court filings are on the Court's own site. Reading the two opposing briefs on a contested rule is one of the fastest ways to see what is genuinely in dispute.
State sources. A great deal of contested policy is made by states rather than Washington, and the federal sources above will not cover it. Every state publishes its legislative record, and most have an equivalent of the CBO producing fiscal notes on proposed bills. The National Conference of State Legislatures maintains comparison tables across all fifty states on most major policy areas, which is usually the quickest way to check whether a claim about what states are doing is accurate.
Inspectors General. Nearly every federal agency has an independent watchdog publishing its own investigations. These are narrower than GAO reports and often more pointed, because an Inspector General is examining the agency it sits inside. Oversight.gov collects them in one searchable place.
None of these documents needs to be read cover to cover. CRS reports have a summary on the first page. CBO scores lead with a table. GAO reports open with "What GAO Found". Federal Register notices carry a plain-language summary before the legal text.
The habit worth building is small: when a claim rests on a number, spend two minutes finding where the number came from. More often than not the source is public, free, and clearer than the argument being made about it.