Y'know, I didn't even realize Walker was pulling a Jeb Bush and still undeclared.
Latest 1-month poll aggregates, courtesy of RCP:
Republican Party:
Bush -- 13.2%
Walker* -- 11.2%
Rubio -- 10.8%
Carson -- 9.5%
Huckabee -- 8.7%
Paul -- 8.0%
Cruz -- 5.8%
Trump -- 4.3%
Christie* -- 4.0%
Perry -- 3.2%
Fiorina -- 2.0%
Santorum -- 2.0%
Kasich* -- 1.7%
Graham -- 1.2%
Jindal -- 1%
*indicates this candidate is not yet formally running for President
Worth noting that the latest poll in the batch, a FOX News poll from 6/21-6/23 has Trump at 11%, riding the publicity wave from his announcement. That puts him second only to Bush with 15%. Huckabee and Santorum seem to be fading into irrelevance. Huckabee's peak was at 17% in February, and Santorum hasn't been above 5% since April of last year.
Democratic Party:
Clinton -- 62.4%
Sanders -- 12.3%
Biden* -- 12%
Webb -- 2.3%
O'Malley -- 2.0%
Chafee -- 0.9%
Sanders has gained a couple of points in the latest polls, up around 15 now. But make no mistake, unless something tectonic happens in this race, Hillary can focus more on picking and vetting a veep candidate and less on the actual primary. If she's smart, she won't start attacking specific Republican candidates until the pack thins out a bit.
Ultimately, the circus may not matter, because in head-to-head polling, Clinton is beating all potential GOP challengers at this point:
Hillary Clinton vs....
Jeb Bush: Clinton +5.5
Scott Walker: Clinton +7
Marco Rubio: Clinton +4.2
Rand Paul: Clinton +3.8
Ted Cruz: Clinton +8
Mike Huckabee: Clinton +5
Chris Christie: Clinton +10.7
Ben Carson: Clinton +10.7
No polling data available yet for Clinton vs. Trump.
Now...let's go back to the GOP race for minute. The overall polls are important, but let's not forget the importance of the first few primary races. A top-3 finish in Iowa, NH or SC can propel an also-ran into frontrunner status (i.e. Rick Santorum), and likewise failing to get a top-3 finish in any of the three races can make an otherwise credible campaign look like a paper tiger (i.e. Herman Cain, Michelle Bachmann, Rick Perry, et al).
So with that in mind, here's the current poll aggregates for those state primaries:
Iowa:
Walker -- 18.3%
Rubio -- 9.8%
Huckabee -- 9.5%
Paul -- 9.3%
Bush -- 8.5%
Carson -- 8.5%
Cruz -- 6.8%
Santorum -- 4.7%
Trump -- 4.5%
Christie --4.3%
Perry - 3%
Fiorina -- 2.8%
Kasich -- 2%
Jindal -- 1%
Worth noting here that the most recent poll in this batch was from 6/8, prior to Bush, Graham, Trump and Jindal formally declaring.
New Hampshire:
Bush -- 15%
Walker -- 10.8%
Paul -- 9.6%
Rubio -- 9.4%
Trump -- 8.8%
Carson -- 5.2%
Christie -- 5.2%
Cruz -- 4.8%
Fiorina -- 4.2%
Huckabee - 4%
Perry -- 2%
Kasich -- 1.3%
Santorum -- 1.3%
Jindal -- 1%
This batch includes data as recent as 6/22, so it captures the Bush and Trump announcements. Interestingly, it also captured the Lindsey Graham announcement, but Graham polled at 0.4% (i.e. 2 of the 500 respondents) in that set.
South Carolina:
Bush -- 13.7%
Walker -- 13.3%
Graham -- 11%
Cruz -- 8.3%
Carson -- 7.7%
Huckabee -- 7%
Rubio -- 6%
Paul -- 5.7%
Christie -- 5.7%
Trump -- 2%
Santorum -- 1.5%
As with Iowa, the most recent polling data in the aggregate was from 6/8.
The big takeaway from all this for me is that Scott Walker very much has a chance to be the alternative to Jeb Bush in this race. He's currently polling in the top-3 in all three early primary states, which is impressive in itself. Even Jeb Bush can't claim that. A win in Iowa burnishes his conservative credentials (although I'd wager it has as much to do with regionalism as anything), and a followup top-3 finish in New Hampshire would allow him to claim "electability". A further top-3 finish in SC would indicate that he can do well among the party's Southern base.
Now, a lot can happen between now and then (for one, Walker has to actually declare himself a damn candidate). Trump might catch fire and suck some of the air out of the room. Walker could have a major misstep. Rubio could have a solid speech that pushes him past Walker into contention for the early states. But as it goes right now, my nonexistent money would be on Bush and Walker battling down the line till at least Super Tuesday.