Final answer:
Policy gridlock occurs when different political parties control different branches of government, leading to a stalemate due to ideological disagreements and polarization. Gerrymandering and single-issue politics can also contribute to gridlock.
Step-by-step explanation:
Policy gridlock is often a result of polarization and divided government, where different political parties control different parts of the government, such as the presidency and the chambers of Congress. This division can lead to significant policy and ideological disagreements, making it difficult for the government to pass new legislation. Gridlock may also arise from single-issue interest group politics, where inaction or failure to reach a consensus on sensitive issues results in a form of policy-making by non-decision. Additionally, factors like gerrymandering can exacerbate gridlock by creating non-competitive districts which lead to the election of more extreme partisan representatives, who are often less willing to compromise.