My view is that immigration is not necessarily a great closing argument for Trump — and I don’t think it was really the closing argument anyway. Remember, in 2016, Trump’s most controversial immigration idea, the Muslim ban, was proposed during the GOP primary. I think it helped him there. Trump didn’t roll out a super-controversial immigration idea on the eve of the general election, and I’m not sure that would have helped. I don’t think Trump intended to roll out his birthright citizenship idea two weeks before the election. I think that happened to be asked by Axios and he didn’t back away from it.
I went to one of Trump’s rallies this weekend, in Indianapolis. The message I heard was more 1.) The economy/the country is doing great under my leadership; and 2.) Democrats are radical socialists (meaning they want to redistribute money/wealth). He didn’t mention birthright citizenship. I think Trump’s closing message is much better understood as “culture war” than immigration.