If I were writing for him, it would look something like this:

When I began this campaign, I believed with all my heart that I was the candidate who could lead this country into a New American Century.  This journey has only reinforced that belief.

Yet, as important as becoming president is to me, it is not as important as the even bigger goal of doing whatever I can to make our country stronger.

So, instead of a final sales pitch, I would rather use my remaining time to say that there is nothing more crucial than for Republicans to stop Donald Trump from representing our party.

In no uncertain terms, then: I denounce him.  I denounce his message.  I denounce his tactics.  And I denounce his campaign.

In light of recent—and not-so-recent—events, I furthermore revoke my pledge to support him if he is the nominee.  And, if I am the nominee, I will refuse his support, even if he offers it.

My duty to my party is strong.  But my duty to my country is stronger.  I am an American above all else.

That means I must take whatever legal, ethical, and moral action is necessary to stop this man from poisoning conservatism—and from poisoning the United States.

Thank you.  And God Bless America.