Where were the mass protests when Obama became #1 in immigrant detentions and deportations in American History? Did we hear anything on MSNBC, CNN, or any other MSM outlet as these massive detention and deportation centers were built under Obama's watch? Trump now has at is disposal the most massive detention and deportation machine imaginable and he didn't have to anything to get it built.
At least George W. Bush understood that illegal aliens were essential to the economy. Obama's high-fiance masters don't use migrant labor, so he didn't lose any support with his deportation program. Mayors, on the other hand, depend on local business owners for their political support and THEY depend on cheap immigrant labor who can be paid less than minimum wage with no benefits. However, going after Obama would've been political suicide because you can't be critical of the leader of your Party unless you don't want to keep your job. It would've been the same way with Hillary, although I think some might have spoken out if they were running in a close race with a Republican. However, now that Trump is President, they can come out with their fists swinging in order to convince their constituents that they give a damn about human rights, which of course, they don't.
This is all academic anyway because if Trump wants to expand on what Obama already started there isn't a whole lot individual cities can do about it short of hiding refugees and illegal aliens in attics and basements. "Sanctuary City" isn't even a legal designation so if Homeland Security wants to round people up and send them back to wherever they came from, there isn't really any legal cover for the cities themselves to stop them.