The pro-choice movement can learn something from the experience gay marriage debate in Massachusetts. When the Massachusetts supreme court legalized gay marriage there were immediate attempts to pass a state constitutional amendment to ban it. While the Massachusetts legislature is solidly Democratic, they aren't all progressives and some are down right conservative. In the first vote[1] a bill banning gay marriage passed.
The political math worked something like this. The conservatives voted for it, the progressives voted against it, the moderates voted what they thought was safe. Conventional wisdom was that the safest vote was against gay marriage. But then something happened.
In the next election several anti-gay legislatures lost their seats to candidates who ran in part on marriage equity, while everyone who voted against the ban kept their seat. This changed the conventional wisdom on what the "safe" vote was. The next time it came to vote the ban failed and failed badly enough that the anti-gay folks gave up trying to get the amendment through the legislature.
This I believe is a good model for what we ought to be doing in places like South Dakota on the issue of abortion. We need to fund pro-choice candidates against as many of the anti-choice legislators in South Dakota as possible. The goal isn't to win them all, but to change the conventional wisdom as to what is the "safe" vote.
Polls show South Dakota residents are split 50/50 on the issue. If the netroots and pro-choice movement made a concerted effort we should be able to help swing some state legislature seats to pro-choice Democrats. My question is what if any groups out there might be trying to do this in South Dakota and how can we give them money?
[1] Amending the constitution in Massachusetts requires the bill to pass twice in two consecutive assemblies.