WASHINGTON (CNN) -- Citing "changing times" and the need for "changing tactics," Senate Republicans emerged from a closed-door strategy session Tuesday to say they have dropped their opposition to beginning debate on a Democratic resolution that sets March 2008 as a "goal" to ending the U.S. combat mission in Iraq.

A procedural vote to launch the debate is planned for Wednesday morning and debate could continue for the balance of the week.

Meanwhile, Majority Leader Harry Reid, D-Nevada, and Minority Leader Mitch McConnell, R-Kentucky, are negotiating the structure of the debate and which, if any, Republican amendments will be allowed.

"Changing times call for changing tactics," said Minority Whip Trent Lott, R-Mississippi, citing signs the troop "surge" in Baghdad is making progress as the main reason for the tactical change by Republicans. "It's a different set of facts at a different time. We're adjusting."

But Democrats accused the GOP of caving to increasing pressure to allow a full Senate debate on the war.

"Many Republicans find it unacceptable to block debate on the most important issue in the country," a senior Democratic leadership aide said.

But the fate of the bill itself is uncertain. Even Republicans who oppose the war say they don't want to set a timetable that would "micromanage" generals on the ground. In fact, it's possible the Democrats will not be able to win a majority vote in the closely divided chamber and that possible outcome has bolstered Republican confidence in moving forward with the debate, aides and lawmakers from both sides said.