Both are equally correct.
Huh? “Cruz” is never the possessive of “Cruz.”
“Jesus’” and “Socrates’” and “Hercules’” are correct, because they are ancient historical or fictional personages.
For modern people with names ending in “s,” the correct possessive is made by adding “’s” to the name.
John Jones’s house
Mary Winters’s new coat
“Ted Cruz’ failed campaign” is wrong on two counts: “Cruz” does not end in “s,” and Ted Cruz is not an ancient personage.
The signs one sees in front of suburban homes are almost always incorrect:
Correct:
Jones
The Joneses (the family)
The Joneses’ (house)
Smith
The Smiths
The Smiths’
Incorrect:
The Smith’s
The Jones’
Pathetic:
The Jone’s