At last night’s Democratic debate Hillary Clinton’s electoral steamroller finally hit a speed bump. With a growing lead in most polls, a powerful fundraising operation, and a developing air of inevitability her opponents were forced to go on the offensive.

And, aided by moderators Brian Williams and Tim Russert, they did just that, criticizing her on everything from Iran to social security and even a plan to give illegal immigrants driver’s licenses. As a result Hillary was on the defensive the whole night and sounded scornful and even angry at times.

But what stood out, was Hillary’s inability to give a straight answer. Her habit of seeking to have it both ways came to the fore and just may have given her opponents the opening they have been seeking in this campaign. If Hillary begins to stumble we may look back on this debate as a turning point.

Hillary had already developed a reputation as a cagey politician who often refused to commit to policy specifics. And she has faced criticism about many of these issues in previous debates. But in the past she was able to deflect these attacks with stronger answers and a sense of humor.

Last night, however, she could not assume that laid back persona. It appeared that the criticism was getting to her. From the start her voice seemed to rise up a notch and take on a harder edge.

As the debate played out a pattern developed. Hillary would be challenged on an issue and she would seek to defuse those criticisms often by ratcheting up her attacks on President Bush and Republicans. Obama and Edwards, however, frequently pointed out that Hillary was trying to have it both ways and that it was time to have a President who was honest with the American people. On a number of issues Hillary refused to be pinned down or give a straight answer.

On Social Security she continued to cling to her mantra of “fiscal responsibility.” She seemed testy and uncomfortable when questioned about why she had refused to put any reform options on the table yet seemed to consider raising the payroll tax in conversation with an Iowa voter.

Instead of taking a stand, she claimed that the whole issue was a “Republican trap.” But Tim Russert noted that her husband had spoken of a “looming fiscal crisis” in social security in 1998. Obama jumped in to assert that the issue was demographics not fiscal responsibility and that everyone on stage was opposed to privatization. Fixing problems required honesty not a fear of GOP talking points.

When Russert brought up Congressman Charlie Rangel’s reform of the Alternative Minimum Tax Hillary once again attempted to straddle. She praised Rangel for his efforts but refused to take a clear position on the specifics. As part of a rambling and confusing answer she claimed that Republicans didn’t care about the middle class and that the issue was complicated because there were “a lot of moving pieces.”

But the issue that really tripped up Hillary and ended the debate on a disastrous note for her was New York Governor Elliot Spitzer’s plan to give illegal immigrants driver’s licenses. Tim Russert again used Hillary’s own words to challenge her by pointing out that she had told an editorial board that the proposal made “a lot of sense.”

Hillary quickly blamed the problem on President Bush’s failure to achieve comprehensive immigration reform but seemed supportive of the proposal. Only Senator Dodd spoke up in opposition. But no sooner had Dodd spoken than Hillary jumped in to claim that she didn’t support the proposal but she understood why Spitzer had brought it forward.

When challenged on this confusing claim, Hillary unsuccessfully tried to backtrack and clarify her position. Instead of offering a clear yes or no she complained that people were trying to play “gotcha.” This allowed Edwards to get in one of the zingers of the night: “Unless I missed something, Senator Clinton said two different things in the course of about two minutes.”

Edwards’s quip seemed to capture the entire debate. On the night before Halloween, Hillary’s mask fell off. When challenged she responded with scorn and evasion instead of honest and straightforward answers. She has given voters a glimpse of her less polished side and her opponents an opening to change the nature of the race.

Let’s hope that voters were watching and that her opponents don’t let up.