Just a few hours after I wrote about Elizabeth Warren’s consistent lead in the polls over Scott Brown yesterday, the Boston Herald released its poll showing Brown back in the lead. The poll has Brown up by six among registered voters and four among likely voters. Mark Blumenthal suggests the sample sizes are partly to blame for the poll variation, and that the polls tell us one thing–the race is close:

The five other polls have shown Warren leading by margins varying from two to six percentage points. Relatively small sample sizes likely contribute to the variation. All but one of the new surveys sampled from 400 to 600 likely voters, for reported margins of error ranging from +/- 4 percent to +/- 5 percent.

When combined in the HuffPost Pollster Trend chart, designed to smooth out the random variation inherent in most polls, the new surveys show a virtual dead heat, with Warren just a half percentage point ahead of Brown (46.2 percent to 45.7 percent).

That will account for the attention the two candidates’ first debate will attract tonight. It will also be a good test for the question I mentioned yesterday: Warren’s populism is the only polling advantage she seems to have over Brown, who voters say is running the more positive campaign, has closer ties to the state than Warren, and has a high approval rating. So if Warren’s only advantage is her middle-class focused, soak-the-rich message, will that be sufficient to win enough public support?

As Jonathan wrote this afternoon, both Brown and Connecticut Republican challenger Linda McMahon will have to rely on ticket-splitting Democrats, since there simply aren’t enough Republican voters to put them over the top in their two states (in Brown’s case, as I wrote yesterday, Republicans make up only about one in ten voters). The Herald talked to some Democratic and independent Massachusetts voters about Brown, and heard exactly what Brown needs to hear to win this election:

“I wasn’t too sure of him at first, but he’s been very independent,” said Jo Ann Dunnigan, a longtime Democrat and President Obama supporter from Fall River who participated in the poll, conducted Sept. 13-17….

“I like the fact he grew up poor and knows what it means to have problems in your family,” said Valerica Stanta, a self-described independent from Haverhill who supports Obama and took part in the poll.

That will make it more difficult for Warren to paint Brown as the corporate candidate, which she is trying to do. Because Warren does not have Brown’s charisma, she’ll be at something of a disadvantage at the debate. She’ll have to rely on hammering home her campaign message, but it turns out there’s more bad news for Warren’s prospects at convincing the electorate:

Warren is viewed favorably by 48 percent of voters — a 14-point increase from nine months ago — but her unfavorable rating has also increased seven points to 34 percent. And three of 10 registered voters say Warren’s views are “too liberal.”

Stanta said she has a “trust” problem with Warren because of her differing explanations for why she listed herself as an American Indian minority in law school directories. “When they avoid explaining exactly what is going on, I don’t feel comfortable,” Stanta said.

Apologies for stating the obvious, but if Warren has a “trust problem,” she’s in trouble–all the more so because of her weaknesses in other areas. Additionally, Warren is too liberal for nearly a third of Massachusetts? Her class warfare may have helped her some, but perhaps even her deep blue state can only take so much bashing of business owners during an economic downturn.

If voters already find her untrustworthy and overzealous, tonight’s debate, which will be on C-Span at 7 p.m. eastern, will be her best chance to improve voters’ perception of her communication style just as much as her substance. But if her Democratic National Convention speech is any indication, that will be no easy task.