John F. Kennedy identifies three main pressures that discourage political courage in senators:
1) The desire to be liked and the pressure to "go along" with one's fellow legislators and avoid criticism or abuse.
2) The desire to be re-elected and the obligations senators feel to supporters and constituents whose happiness and security may depend on the senator's success.
3) Pressure from constituents, interest groups, and voters, whose demands and opinions cannot be entirely ignored but may conflict with acting in the national interest. Kennedy argues that senators must balance representing constituents with exercising their own judgment.