Sen. Jim Bunning at Immigration Press Conference, originally uploaded by Rob Bluey.

Senate Majority Leader Harry Reid (D.-Nev.) caved under pressure tonight after conservatives mounted an aggressive campaign over the past week to extend debate on the amnesty bill.

Led by Sen. Jim DeMint (R.-S.C.), a group of conservative senators made repeated pleas to prolong the time they have to read and amend the bill. Part of the problem was that Reid and his Democrat colleagues failed to produce the final text of the bill.

The delay means senators will have to return home next week, which could put them in front of hostile crowds who have reacted angrily to the legislation, which was drafted in secret by the White House, Sen. Teddy Kennedy (D.-Mass.) and a few Senate Republicans.

“The bill is critically important to the American people, and to railroad it through the Senate would be unthinkable,” said Sen. Jeff Sessions (R.-Ala.), who joined Sen. Jim Bunning (R.-Ky.) earlier today at a Capitol Hill press conference. “The recess week will provide some time for senators and the American public to become familiar with this extraordinarily complex legislation and to better understand its consequences.”

UPDATE — 9:34 p.m.: I should have noted earlier that, as expected, cloture was invoked today by a vote of 69-23. This vote gives you a pretty good idea of the die-hard opponents. Starting out at 23 isn’t bad. There are many Republican targets and a few moderate Democrats who could be wooed to vote against a final product.