1) Renew the current law. No real upside for any legislator, but no significant downside.
2) Reject the current law. Very little upside: the doves, paranoids, libertarians, and tea party activists who might actually care about this options are insignificant minorities within the electorate. Significant downside: it opens a legislator up to all sorts of "<insert incumbent name here> is making it easier for terrorists" attack ads regardless of the actual merits of the argument.
3) Amend the current law. An effort which would have needed to start a while ago. With enough bi-partisan support this could have limited the downside risk and enabled supporters to make the sort of "we are being smart about protecting ourselves form terrorists while protecting liberties" arguments that would have electoral upside, but given the current legislative climate it would have been a hard task to get the early defectors form the status quo which would have provided a bit of momentum.