He’s looking at 2016. If Cruz goes down in flames over defunding, Rand looks like the conservative who is not too far out there. I think he’s miscalculating, but I’m guessing that’s his thinking.
If you’re right, that means he’s putting his selfish political ambitions above principle. Which includes trying to step on Cruz to make himself look good.
From every angle it’s repulsively self serving and cowardly.