Parsing the president on the border wall

A lot of conservatives are distraught that the president is sounding like he's caving on the border wall.  There has been indication that he might cave.  Last time he caved on something he said he would never sign bad legislation again.  But he's seemingly been very bi-partisan in lame duck legislation signing so far this year. He's even been conciliatory, at times.  But seemingly he's going to capitulate now.

But less than an hour ago the president tweeted this:

The Democrats, who know Steel Slats (Wall) are necessary for Border Security, are putting politics over Country. What they are just beginning to realize is that I will not sign any of their legislation, including infrastructure, unless it has perfect Border Security. U.S.A. WINS!

— Donald J. Trump (@realDonaldTrump) December 20, 2018

Seems like even though Mitch McConnell caved in the senate, the president will not sign a continuing resolution to keep the partial government shut down from happening until at least February (when the Democrats will control congress).  I don't get McConnell except to say that clearly border security is not a priority for him.  But you'd think since he's supposedly a shrewd political tactician he'd understand the value of a win, the value of the base and the value of using the lame duck session to maximize what Republicans can achieve over the next two years.  Apparently not.

But look back at what the president just tweeted.  It seems when he says "sign any of their legislation" he is referring yo Democrat legislation, not what Mitch McConnell just passed.  That's a possible interpretation.

If that's the case, the president could be gearing up for 2020 as a referendum on the feckless, fake border security stance of Democrats.  It's a good issue for him.  But it relies on border security voters not caring or forgetting that he did not stand up to feckless, fake border security Republicans this year.  That might turn out to be a political miscalculation by the president, not his first, but by far his most egregious. 

It could be some other calculus, but if that's the case, I cannot see the angle.  Then again, perhaps the president will indeed veto the legislation.  That would be a sign to his supporters that he has not given up the fight, and what we are seeing is just tactics with some design.

Time will tell.