The right to petition the government is in the First Amendment, and almost everything about exercising it professionally is regulated. This article traces the two federal registration regimes and the line between them. It begins with the Lobbying Disclosure Act's definitional machinery, the lobbying contact, the twenty percent test, and the dollar thresholds, and explains why the statute's biggest feature is what it does not cover, including grassroots campaigns and the strategic advice that shapes a lobbying campaign without triggering registration. It then turns to the Foreign Agents Registration Act, a 1938 statute aimed at Nazi propaganda that spent decades dormant and has been enforced seriously since 2016, and to the three exemptions that decide most FARA questions. Later sections cover gift rules and the revolving door statutes, the Supreme Court's steady narrowing of federal corruption law through McDonnell, Skilling, Percoco, Ciminelli, and Snyder, campaign finance and pay-to-play restrictions, the tax and appropriations rules governing nonprofits and federal grantees, and the state regimes that are often stricter than the federal ones.