Persuasion and ideological voting in legislatures

American legislators are generally thought to be ideologues who take consistently partisan positions, but recent research suggests they are also pliant targets of persuasion campaigns by special interests, lobbyists, fellow legislators and even academics. This paper explores this seeming discrepancy. First, we revisit the credibility of findings of legislative persuasion to determine whether legislators’ positions can be changed and, if so, whether such changes are robust and long-lasting. Second, we examine whether persuasion works against or alongside ideology. Finally, we interview legislators to hear their experiences as targets of persuasion. We conclude that legislative persuasion can be long-lasting and found on bills other than those targeted by advocates. Persuasion can increase ideological position-taking and polarization by allowing legislators to better sort into positions consistent with their broader ideology. Finally, persuasion works through different mechanisms, including learning about policy expertise or electoral considerations, that vary in relevance across legislators. Our findings suggest legislative persuasion may play a key role in how parties, interest groups and constituents drive polarization.