He announced his decision on Twitter earlier today.

According to NewsWest 9, O'Rourke says he will support whoever gets the Democratic nomination.

In his tweet, he said, "Our campaign has always been about seeing clearly, speaking honestly, and acting decisively. In that spirit: I am announcing that my service to the country will not be as a candidate or as the nominee."

The Democratic race has been a crowded one and O'Rourke just could not make headway.