Other choices would be a Hail Mary pass with Dr Carson in hopes of getting some black votes but the stage presence with the two didn't seem to work.
I am still waiting for the Rubio endorsement and with Kasich in Ohio. both with delegates to throw his way.
Christie gets a high profile position for sure either way.
If Rubio had one ounce of street smarts he would endorse Trump. For a guy from the barrio or there abouts he should see what is really happening and realize he has to change a lost game. Playing defense with Karate Man will only bring another level of defeat.