When people drop out it frees up their delegates to vote for whom ever they want although they are expected to vote for whoever their candidate has announced support for. Thus if everyone else in the race dropped out except for Cruz and endorsed him then he would win. The problem with this is that the establishment is against both Cruz and Trump; however, when forced to choose between the two it is more likely to throw its support behind Cruz over trump. Many may be confused by how Trump got endorsed by Christie. If no one endorsed trump and literally everyone endorsed another candidate and this resulted in Trump being trumped in delegate count then he would flip out and run on a 3rd ticket. So instead the desision to give him some support but in such a way that does not have any real effect in delegate allocation will create sufficient illusion of balance. Obviously the preferred solution for the RNC would be that Cruz was not doing well as they would be happy to have Rubio as he is an establishment Republican. However as this is not the case they will likely try to broker a deal with Cruze over his VP pick in order to hand him the win. The real question is how long will this go before the party backs down and feels that it can get behind Cruz.