Clinton
Democratic presidential candidate Hillary Clinton is quickly losing her lead over rival Bernie Sanders nationally. Above, Clinton speaks during a campaign rally at Iowa State University in Ames, Iowa, Jan. 12, 2016. Reuters/Scott Morgan

With less than three weeks until the Iowa caucuses mark the opening of the 2016 presidential primary voting season, Vermont Sen. Bernie Sanders is closing in on Hillary Clinton’s national lead. Clinton has been the clear Democratic front-runner for months, but recent polls show her margin slipping much faster this year than it did when she ran in 2008, the Washington Post reported Thursday.

In 2008, when Clinton was running against then-Sen. Barack Obama and former Sen. John Edwards, she began her White House bid with confidence and led the Democratic field through much of the early months of the campaign. But as Obama began to gain momentum, Clinton slipped and wound up placing third in the Iowa caucuses. After that, her campaign had a bumpy ride and she ultimately lost the nomination.

This time around, Clinton entered the race after significant buildup from fans, celebrities and other politicians urging her to run. Many have considered her the inevitable nominee from the start, and she has struggled to avoid appearing complacent as she has faced a surprisingly competitive challenge from Sanders. (Former Maryland Gov. Martin O’Malley is, of course, still in the running as well, but he has trailed the other two candidates for months.)

However, the assumption Sanders was simply good debating practice for Clinton disappeared quite a while ago. While Clinton remains ahead of Sanders in national polling, a New York Times/CBS poll this week showed her lead shrinking significantly. In the survey, 48 percent of Democratic primary voters supported Clinton compared with 41 percent for Sanders. Just a few months ago, Clinton was often leading Sanders by double digits.

The Washington Post’s analysis shows at this time in 2008, when Clinton was still up against two strong opponents, she was doing much better nationally than she is now. In Iowa, Clinton is doing a bit better than she was in 2008. But in New Hampshire, where Sanders enjoys an almost-home turf advantage from the state’s proximity to Vermont, Clinton is doing much worse than she was during her last bid.

After coming in third in the Iowa caucuses last time, Clinton’s lead in New Hampshire plummeted, the Washington Post showed in its graphs, but she regained some points and managed to win there.

Clinton’s campaign has clearly been feeling the crunch and has stepped up its rhetoric against Sanders in recent weeks. They have sent out multiple emails to supporters warning them Clinton could lose in the early primary states, and Clinton’s daughter attacked Sanders over his healthcare plan at a campaign event this week.

The former secretary of state also raised the alarm Thursday about what it said was a “surprising” negative ad from Sanders’ team. “We were very surprised today to see that Bernie Sanders had launched a negative television advertisement against Hillary,” said Robby Mook, Clinton’s campaign manager, in a conference call with reporters Thursday. “We were particularly surprised because he had personally pledged and his campaign had pledged to never run a negative advertisement.”

In the ad, Sanders describes “two Democratic visions for regulating Wall Street,” which Mook said clearly referred to Clinton. Sanders has often boasted that he “has never run a negative ad, and his campaign adviser Tad Devine told the New York Observer last year that “the day he would have to get into a negative exchange with Hillary Clinton is the day the campaign is over.”

In December, the Sanders campaign also pulled a negative ad after it received attention for going against his “no attack ad” promise.

The Democratic presidential candidates will get a chance to face off in person Sunday at the last debate before the voting begins next month.