I think the idea is that both issues will trend heavier to drive voter turnout for voters who REALLY care about those issues, and that there is enough of a correlation between opinion on those issues and party affiliation that it'll boost D turnout more than R turnout, giving a boost to the Ds.
Much like in 2004 there was a concerted R strategy to get gay marriage initiatives on the ballot in many states, thinking that the people who were REALLY against gay marriage would be highly motivated to make it to the polls, and that the turnout advantage would help the Rs.
This is yet another result of the polarization.
Years ago (basically pre-2004) everything in politics was about appealing to the "middle voter". The basic theory was:
Pick an issue, say abortion. If you lined up all 300-some-Million Americans from the most radically pro-choice on the far left to the most radically pro-life on the far right then went to the exact middle of that line you'd find someone whose view of the issue was (speculating, no idea where exactly the "middle voter" would be):
- Felt the line should be at 27 weeks (roughly end of 2nd trimester)
- Abortion more-or-less unlimited prior to that line, more-or-less prohibited after
- Parental notification with limited judicial exceptions
- Exceptions for Rape, Incest, life or health of the mother, or severe disability of the child
So prior to 2004 or so the general rule in politics was that you wanted to appeal to that "middle voter" and if you were successful at that, you'd get either:
- A majority made up of the "middle voter" and everyone to the right of them if you were an R, or
- A majority made up of the "middle voter" and everyone to the left of them if you were a D.
This theory inherently had a moderating influence on parties/policies because basically the theory was that whichever party was farthest from the "middle voter" would alienate the "middle voter" and thus lose, Ie:
- If the D's pushed for abortion on demand paid for at taxpayer expense up until the umbilical cord was cut with no parental notification and the R's pushed for a line at 20 weeks instead of 27, the theory was that the "middle voter" would be more comfortable with the R's slight (seven week) deviation than with the D's 13 week deviation and addition of taxpayer expense.
- Conversely, if the R's pushed for a total prohibition on abortion and severe limits on BC while the D's pushed for a line at 34 weeks, the theory was that the "middle voter" would be more comfortable with the D's slight (seven week) deviation than with the R's 27 week deviation and more.
In the immediate above example, note that the party that wins is the party that stays closest to the center.
Then 2000 and 2004 happened. Gore in 2000 focused more on turnout than on appealing to the middle voter and it almost worked. It actually did work with regard to the popular vote but the problem for Gore was that a lot of the extra voters that his campaign turned out were in non-competitive states so all they did was give him a bigger margin of victory in states he won and a smaller margin of defeat in states that he didn't have a chance in.
The Bush people saw what Gore's team had done in 2000 and basically said "we can do better than that" so they spent a substantial amount of campaign resources on various "outreach coordinators". These people went into Conservative areas and basically "beat the bushes" looking to make sure that the conservatives actually voted. For example, prior to 2004 I never saw Republican campaign tables at Gun Shows. Since 2004 you see them at EVERY gun show unless they are specifically prohibited.
This worked really well for Bush in 2004 and basically every campaign since has gone with this theory. Nobody really talks about the "middle voter" anymore, instead everybody simply focuses on Registration and GOTV drives in an effort to make sure their side shows up.
The problem is that unlike the previous theory which had an inherently moderating influence, this new theory inherently radicalizes because you don't excite your side with wonky discussions of 20 vs 34 week bans, you excite your side with fire-breathing radicalism.
