(Bumped, in light of the clarification I've added below. I still think these are important questions, not because they will be the issues driving the race, but because they could affect the math. - promoted by David)
1. Where do you stand on abortion/choice?
2. Where do you stand on same-sex marriage?
3. Where do you stand on casinos and slot machines?
The answers to those three questions will tell us a lot about how viable Baker's candidacy really is. Assuming he beats Christy Mihos in the primary, he's obviously got to bring in a lot of independents and a decent number of unhappy Democrats to win. Cahill's stand on slots (along with Governor Patrick's stand on resort casinos) has given him a huge opportunity to do so -- but the anti-gambling crowd won't go with someone who they see as suspect on social issues.
I hope someone asks those questions at his presser later today. Wish I could attend myself!
CLARIFICATION: Apparently, I was less than clear about why I want to know the answer to these questions, as readers both here and elsewhere have misunderstood why I posed them. So let me be clear: I am not saying that these three issues are what is going to drive the election -- they're not. I am trying to figure out whether Charlie Baker can win. As sabutai has explained, the math is not easy for him as long as Tim Cahill stays in the race. But one possibility that occurs to me is for Baker to pick off some liberals who probably voted for Deval Patrick in the 2006 primary but who hate casinos. If Baker appears solid on hot-button social issues (liberals will not support someone suspect on those issues) but says he will oppose slot machines and casinos, all of a sudden he becomes the last best hope for the anti-casino crowd to keep casinos out of the state. That could let him cut into Deval's base, and that could change the math that sabutai correctly notes is difficult as long as Cahill is viable.