WASHINGTON (CNN) -- A day before they are to cast an extremely sensitive vote on an Iraq war funding bill, neither of the top two Democratic candidates for president would reveal how they will vote.

Facing the choice of either voting for a bill that lacks the timetables for troop withdrawal the left wing of their party is demanding or voting against funding the troops altogether and facing the wrath of possibly everyone else, Sen. Hillary Clinton and Sen. Barack Obama ducked.

At a press conference on the immigration bill, Clinton initially declined to answer a question about the funding bill on the grounds it was off topic.

As she departed the event, she declined to answer because she hadn't "seen the supplemental" and "it hadn't even been introduced as far as I know."

Reminded it won't include timetables, she responded with an edge of frustration in her voice: "When I have something to say, I'll say it, gentlemen."

When Obama departed the Senate floor after delivering a speech on immigration, he told reporters that he hadn't "seen a final product" and didn't want to comment "until I do."

"I actually want to read the provisions before making a statement on it," he said. "All right?"

Other presidential candidates knew how they'd vote.

Sen. Joe Biden said he didn't like the bill but "as long as we have troops on the front line we're going to have to protect them."

But former Sen. John Edwards disagreed. He urged Democrats to vote against the compromise bill, which he characterized as a "capitulation."

Sen. Christopher Dodd released a statement urging his fellow senators to join him in voting against the bill.

"Half-measures and equivocations are not going to change our course in Iraq," he said. "If we are serious about ending the war, Congress must stand up to this president's failed policy now -- with clarity and conviction. ...

"I will continue to fight for a firm deadline that is tied to funding which will allow for a responsible redeployment of U.S. combat troops in Iraq -- because that's the only way to responsibly bring this war to a conclusion."