With a new poll showing falling support for the Gang of Eight comprehensive immigration reform bill, Senate Majority Leader Harry Reid has announced an accelerated schedule in which the Senate would take a final, up-or-down vote on passing the bill by the end of next week.

"I’m just telling everybody that we’re going to either file cloture on this on Friday or Saturday or Sunday or Monday,” Reid said as the Senate opened its morning session. Filing for cloture means that a final vote would be held three days later. So if Reid filed for cloture on Monday, June 24, a final vote on the bill would be held on Thursday, June 27. The Senate’s July Fourth break starts the week after.

Reid warned his fellow lawmakers that if they want to consider amendments to the Gang of Eight bill, they need to be prepared to work virtually nonstop between now and then. "This may not be one of our normal weekends,” Reid said. “We’ve got to move forward on this legislation.”

Why? Debate in the full Senate only started last week. Why is Reid rushing to pass such a sprawling, multifaceted piece of legislation in such a short period of time? Is there an emergency?

There is no obvious, pressing reason for Reid’s schedule. But as he spoke, there were signs that popular support for immigration reform is slipping. After months of polls showing widespread support for some elements of reform, a new CNN survey showed a bare majority, 51 percent to 45 percent, supports the Gang of Eight bill. Perhaps more ominously, the poll found strong support for prioritizing border security above a path to citizenship for currently-illegal immigrants. Independents favor security before a path by a two-to-one margin, and Republicans support it by a three-to-one margin. Democrats favored a path to citizenship over security, but by the barest of margins, 50 percent to 49 percent. Overall, CNN found that 62 percent of the public favors prioritizing security before a path to citizenship, while 36 percent favored a path over security.

The polls might not have much more time to change, if Reid goes through with his schedule and immigration reform gets a final vote by the end of next week.