He may have started a list of lawsuits from Democrats, including Kamala Harris, to challenge this emergency measure.
https://www.yahoo.com/news/trump-will-sign-spending-bill-but-endrun-congress-to-build-wall-213834096.html https://www.yahoo.com/news/trump-will-sign-spending-bill-but-endrun-congress-to-build-wall-213834096.html