Because the democrats made the mind-numbingly stupid decision to pivot right like they always do, this time on immigration. No more, “Building the wall is racist,” no more, “No one is illegal,” instead it was, “We’re the ones who are actually going to build the wall, Trump’s all talk.” To this end, they attempted to pass a bill that would have greatly expanded the president’s ability to crack down on immigrants.

They figured, as they always do, that everyone would simply fall in line behind them as the “lesser evil.” Instead, the result was that they undermined their argument that stricter immigration laws were grounded in racism (which they are, of course), and failed to distinguish themselves from the Republican position. Many Latinos have conservative positions on other issues, and, perceiving little significant difference between the two parties’ stances on immigration, they voted based on other, less important cultural issues where there was a meaningful difference. It’s worth noting that some people have the sentiment, “We came here legally so they can too,” and it was only when there was (correct) messaging that cracking down on undocumented immigrants was a slippery slope that would endanger legal immigrants that they were able to be persuaded to set aside other cultural issues. This messaging was abandoned because it was considered potentially alienating the the oh so precious (white) moderate Republicans, who also didn’t vote for them, because they’re nonexistent/unwinnable.

This is one of many, many examples of how moving towards the “center” can alienate voters and lose votes, especially when it involves acting against your constituents’ material interests.