This is silly. The leftists are more like Canadians and the anti-choicers are more like Latin American states, as Canada has no restrictions on abortion and most Latin American states have extreme anti-abortion laws. I don't see any reason why the states shouldn't have MTG's divorce and the pro-choice states can ally with Canada and Mexico, while the red states can ally with right wing Central and South American states.
In case you don't know which is which, the people who would ally with Canadians and Mexicans would be in Colorado, Kansas, New Mexico, Nevada, probably Arizona, California, Oregon, Washington, possibly Montana, Minnesota, probably Wisconsin, Illinois, Kentucky, Michigan, as of today Ohio, Pennsylvania, Virginia, Maryland, Delaware, New York, New Jersey, Vermont, New Hampshire, Connecticut, Rhode Island, Massachusetts, and Maine, 27 states, plus Hawai'i and Alaska. Except for Hawai'i, these states all share borders with each other and/or Canada or Mexico, so they could be a huge contiguous nation if they wanted to. Note that this would work with or without Montana, Wisconsin, or Ohio. It would really isolate Indiana, though. If North Carolina and Georgia want to join up, they can, though this will really isolate South Carolina.
Of course, the rest of the states could form a banana republic.