Republicans think states should be allowed to ignore federal laws they think are unconstitutional.

A YouGov poll finds, overall, 44% of Americans say "no" when asked if states should be allowed to disregard federal laws they feel run afoul of the Constitution. However, when those numbers are broken out along partisan lines, 55% of Republicans support nullification while 62% of Democrats oppose it. 

Those numbers become even more stark when you look at how they break out along regional lines.

The south and the midwest are the most supportive of nullification, though in both regions people are marginally more likely to oppose than support nullification. Opinions in the northeast and west are, however, much more likely to be hostile to nullification. This correlates with the partisan split, as the south and midwest are more heavily Republican than the west and northeast.