Wisconsin Gov. Scott Walker's (R) seven-point lead in his reelection race this fall has evaporated in just two months, according to Marquette Law School poll released Wednesday that shows the tea party idol tied with likely Democrat opponent Mary Burke at 46 percent.

Wisconsin Gov. Scott Walker in his Madison office last June. (Scott Bauer/AP)

The poll — full results here — is being pointed to by Democrats around the country as evidence that Walker is deeply vulnerable. They shouldn't get too excited. A dive into the poll's innards finds Walker's recent losses are concentrated among voters who are least likely to cast ballots on Election Day.

The survey asked registered voters whether they are absolutely certain to vote in November, very likely, 50-50, or whether they will not vote. Burke leads Walker by 47 to 41 percent among the less committed bloc bloc, reversing Walker's 47 to 35 lead percent with these voters in March. Walker's advantage has been far more stable among those who are "certain" to cast ballots, narrowing from a five-point edge in March to three points in the new survey. Among those who are both certain and enthusiastic about voting, Walker's lead expands to five points.

Certainty about voting more than five months from Election Day is a rough gauge, but the dynamics in Wisconsin match closely with national and historical patterns. Voters under 30 and those with lower incomes are both are among Burke's best groups against Walker but also express less interest in participating and have a track record of lower turnout in both presidential and off-year elections.

There are still some trouble spots for Walker in the data. Voters are divided on his job performance (49 percent approve, 46 percent disapprove) and in their personal impressions of the governor (47 percent favorable, 48 percent unfavorable). Burke's favorable-unfavorable ratings tilt positive at 27 to 22, though a majority of voters in the state still have no impression of her.

Walker's role as a tea party favorite also appears to be a bigger liability today than it was in the 2012 recall fight. Twice as many voters see the tea party in a negative than positive light (48 to 23 percent), a worse margin than before Walker's successful recall election (44 to 32 percent unfavorable-favorable).

Walker isn't immune from a serious challenge. But the poll many Democrats are pointing to as evidence that such a challenge has already materialized may be more than meets the eye.

Peyton M. Craighill contributed to this report.