The new Public Policy Polling survey of Wisconsin shows that Scott Walker has regained leads in his recall election against all challengers, pinning right at the magic 50% mark. He leads Milwaukee Mayor Tom Barrett 50-45, and former Dane County executive Kathleen Falk 50-43, with larger leads against the lesser two candidates in the Democratic primary, Secretary of State Doug LaFollette and state Senator Kathleen Vinehout (PPP also includes a wealthy independent candidate named Hari Trivedi in their poll, and he gets non-trivial support that I believe will outstrip his actual vote total on Election Day).

Part of this comes from the fact that Walker has been running ads touting his success in Wisconsin for months, and he just started running attack ads against Barrett and Falk (but he’s mostly airing the one against Barrett). This speaks to the built-in advantages of the campaign. Walker had a big head start on his rivals in terms of fundraising. While state officials determined whether enough signatures had been gathered to trigger the recall, Walker could raise unlimited amounts, and this gave him a head start that translated into millions of dollars. In addition, the low point of Walker’s gubernatorial record, the anti-union law and the protests it triggered, is by now more than a year old. Opposition activists face a tough road to recreate that energy against Walker. And finally, Walker faces no opposition in his party, while Barrett, Falk, LaFollette and Vinehout bicker amongst themselves for the lead in their May 8 primary.

According to pollster Tom Jensen, the discrepancy between this poll and the last one from PPP, which showed Barrett and Falk nursing small leads against Walker, comes from adding a likely voter screen. The universe of likely voters in this race is more Republican than the universe of registered voters. He also describes a shift among independents:

The other thing is that independents have flipped from our last poll, from supporting Milwaukee mayor Tom Barrett by 12 to going for Walker by three. We’ve seen independents go back and forth on Walker several times over the last year, though I’m not certain what causes that. Walker’s been very aggressive about getting on the air and that may have helped firm up his standing, especially as Democrats fight amongst each other over their nominee.

If you believe that indies are the most likely to be swayed by advertising, that plays into Walker’s built-in advantages. But the sharp rise in likely Democratic nominee Barrett’s unfavorables, from 41-33 to 41-45, is troubling. You can see Falk creep back into the primary race due to this:

Tom Barrett (D): 38 (45)
Kathleen Falk (D): 24 (18)
Doug La Follette (D): 9 (14)
Kathleen Vinehout (D): 6 (6)
Undecided: 22 (17)

Barrett definitely has the advantage, but it’s not locked down yet, and if the two lesser challengers continue to fade and Falk benefits, that could become a real race. That’s especially true if labor, which for the most part supports Falk, decides to move in with some money. Republicans and independents can vote in the Democratic primary in Wisconsin as well, which could skew the numbers.

Perhaps a unified Democratic ticket post-primary will start to regain an advantage, but Walker will have a lot of time to build support, virtually uncontested, for the next few weeks.