That is the topic of my latest Bloomberg column, here is one bit from it:
There is evidence that American attitudes toward immigrants are growing more positive. There is also evidence that simply thinking about immigrants makes Americans less likely to support them, so Democrats may decide to de-emphasize the issue. The intensity of anti-immigration sentiment has helped Republicans take control of all three branches of the federal government, and Democrats would probably prefer for the next big set of political debates to be about health-care policy and additional benefits for women. The American public actually trusts Trump more than congressional Democrats to deal with border security.
There is much more at the link, not all of it pleasant.