Why might a member of congress vote in favor of a bill to pass once it is certain to pass even though he or she had supported previous attempts to scuttle it?

"A member of Congress may strategically want to show support for a bill simply to be able to say that they voted for it when they are running for re-election, even if they were against it. It seems silly, but it works more often than it should, especially with people who aren't paying close attention to those running for office." 
https://quizlet.com/145203013/government-chapter-12-questions-flash-cards/

Because it helps them plan a strategic advantage in the next election