It can become a top priority in year 2,3,or 4 of a Trump or Cruz presidency. Especially after replacement of 1 or 2 Supreme Court justices.
Yes, this is a TOP-Three conservative fight, along with a hundred (or more) other things.
But, it is not nor should it be a top three for Cruz in his run for POTUS.
There is no need for him to focus on every battle - he needs to focus on 3, no more, no less, during his campaign, to make his campaign competitive and focused and effective.
There are millions of conservatives out there that can and do focus on the other hundred (or more) of the other things as *their* top 3.