He has two other sources of immediate money that Congress can't stop him from getting even with a liberal court decision.....by the time he spends that money, it will be at SCOTUS just as the military funding becomes an issue. The three active sources gives him roughly $5B with the military funding being an additional $3+B.
When Congress gave him the $1.3B, they put restrictions on it (last year's budget remember) that it could ONLY be used to fix/repair existing barriers and normal security. He went along with that in order to get the Pentagon increase. Basically, they gave him nothing this time because the same restrictions are on it....and they did the same thing with this current CR that lasts until Sept. The Reps under Paul Ryan and Mitch McConnell told him if he waited until after the elections, they would pass the $5+B bill he wanted for the wall.....Ryan got it passed, but because of the three Reps in the Senate that refused to vote for it (Collins, Merkowski, and Flake...who wanted to screw Trump anyhow before he left), they didn't have enough votes to pass it so McConnell never brought it up for a vote. And Merkowski shouldn't even BE in the Senate except for a liberal judge in Alaska allowing it to happen.....I always believed that Republicans in that State legislature and election board should have sued over that illegal decision.