First, there remains a chance he can stop Trump, however unlikely.

Second, Cruz needs to keep his delegate ground game going. The Trump delegates, most of them at least, are not traditionally Republican and have no real investment in the Republican Party. They are there for Trump. Cruz’s delegates have all typically been heavily involved in the party and the conservative movement.

Trump may get to 1,237, but Cruz’s delegates, should Cruz stay in, have a real chance of writing the rules for the Republican convention and shaping the Republican platform.

As long as Cruz has money coming in and can sustain his operation, he needs to. Trump is his own worst enemy at this point and he is always one interview away from another bad news cycle. Cruz can and should capitalize on that.