yeah. this is a political stunt, not a serious legal argument.
as mentioned, they didn't file it in san francisco by accident. the rubber-stamp kangaroo court there will follow party dictates and send it up to the next level. the democrats can always rely on an easy injunction using this method, as they control this particular court.
but, this argument stands exactly zero chance of working in the long run.
the real question is as follows: why aren't the democrats launching a judicial review? was a deal made around politicizing the issue in a hopeless court battle as a face-saving mechanism?
https://www.nytimes.com/2019/02/18/us/politics/national-emergency-lawsuits-trump.html