The process is easiest to see when a new majority takes office. Its members may agree on a broad promise such as reducing health-care costs but disagree about taxes, coverage, and federal authority. Leaders cannot enact the slogan. They must refer proposals to committees, assemble votes, negotiate between chambers, and work with or overcome the executive under the constitutional process. Party organization helps elect the members; party-in-government coordinates what they do with public authority.

Party leaders rely on incentives and negotiation rather than a legal power to command votes. They can offer committee assignments, agenda access, campaign assistance, information, and help with members' priorities. Members can still defect because of district opinion, state interests, ideology, personal ambition, or disagreement about policy. A platform may guide the agenda, but it is not a statute and does not override the Constitution, chamber rules, or an officeholder's legal duties.

Unified party control can make coordination easier, but it does not erase bicameralism, federalism, judicial review, Senate procedures, or internal factions. Divided government places the presidency and at least one chamber under different parties, increasing the need for bargaining and making credit or blame harder to assign. Neither unified nor divided government guarantees a particular result. This lesson concerns the work being performed: selecting leaders, arranging committees, scheduling bills, and assembling votes are ways of organizing government. The party-in-government lesson later identifies the officials who perform that work and the feedback their governing record sends to voters.

Video lesson: Political Parties: Crash Course Government and Politics #40