The argument that Cruz didn't support Trump is based on the fact that he didn't mention his name in his speech, probably because he believed Trump to be a poor candidate. BUT, that is not at all the same as saying that people shouldn't vote for Trump, or that they should vote for Hillary. Because if you read his speech, he did mention Hillary by name, and it wasn't complimentary:
We have to do better. We owe our fallen heroes more than that. Now, of course, Obama and Clinton will also tell you that they care about our children's future. And I want to believe them. But there is a profound difference in our two parties' vision for the future. Theirs is the party that thinks ISIS is a JV team. That responds to the death of Americans at Benghazi by asking, what difference does it make?
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Hillary Clinton believes government should make virtually every choice in your life. Education, health care, marriage, speech, all dictated out of Washington. But something powerful is happening. We have seen it in both parties. We have seen it in the United Kingdom’s unprecedented Brexit vote to leave the European Union. Voters are overwhelmingly rejecting the political establishment and overwhelmingly rejecting big government. That is a profound victory, and it is one earned by each and every one of you.
So what was going on with Cruz's speech was pretty clear. He wasn't going to sing Donald Trump's praises, or tell people that he was a great guy who had earned their vote. But he was very willing to tell voters how bad Hillary Clinton was, and that her vision was the absolute wrong vision for the country. The subtext was don't consider your vote a vote "for" Trump. Consider it a vote
against Hillary.
No remotely honest person would claim that speech was an endorsement of Hillary Clinton, or that it encouraged anyone to vote for her. Quite the opposite.