They vote ­ but not always. Compared with Americans who regularly cast ballots, they are less engaged in politics. They are more likely to be bored with the political process and admit they often do not know enough about candidates to cast ballots. But they are crucial to Republican and Democratic fortunes in the Nov. 7 midterm elections.

They are the intermittent voters: Americans who are registered to vote but do not always make it to the polls. They differ significantly from those who vote regularly. For one thing, they’re less likely to be married than are regular voters. Intermittent voters also are more mistrustful of people compared with those who vote regularly. They also are less angry with government, though no less dissatisfied with President Bush than are regular voters, according to a survey conducted Sept. 21-Oct. 4 among 1,804 adults by the Pew Research Center for the People & the Press in collaboration with the Associated Press.

The survey also finds large differences between Americans who are not registered to vote or vote only rarely, and intermittent or regular voters. The two groups at the bottom of the voting participation scale are much less likely than regular or intermittent voters to believe that voting will make much of a difference. They also are less likely to agree with the statement: “I feel guilty when I don’t get a chance to vote.”