In the article, O'Rourke did not outright say he is running, be he said things like "I want to run".
O'Rourke's announcement comes five months after his senate race against Republican incumbent Ted Cruz.
Until he challenged Republican Sen. O'Rourke raised more than $80 million in his bid to oust Cruz.
"I think that Lincoln had only one term in the House and lost a Senate race", said Gingrich.
O'Rourke refused donations from outside political groups and shunned pollsters during his Senate campaign.
O'Rourke joins an ever-growing field of Democrat presidential candidates, which includes Sens. John Cornyn in 2020, but he chose to seek higher office instead.
And he was the only presidential prospect interviewed in February by Oprah Winfrey, who appeared genuinely excited about the prospect of an O'Rourke White House run. "It's just how I think, how I find the next step". He visited with students in the key swing state of Wisconsin.
When President Trump held a rally in the city, which already has portions of fencing, O'Rourke held a counter-rally.
It was the kind of high-energy, off-the-cuff style that made him a sensation in Texas, but O'Rourke also was clear that he doesn't believe in strict immigration policies - drawing a policy distinction that could allow him to clash with President Donald Trump on the issue. "Democrats have to stand for their new set of policies", he said, describing those collectively as "making America socialist".
"We can free ourselves from the distinction of being the country that imprisons more of its fellow citizens than any other country on the face of the planet", O'Rourke said.
"The only way for us to live up to the promise of America is to give it our all and to give it for all of us", the 46-year-old said in a video.
It wasn't the first time O'Rourke generated national attention for taking on Trump. The lunch counters, cafes and town squares aren't going anywhere. The clip went viral.
He predicted that O'Rourke will not win the Democratic nomination, but even if he did, he would not be able to carry his home state against Trump and would lose the general election.
As his campaign takes shape, O'Rourke has to put the focus of his White House bid on the American people, not his own ambition.
Several polls of hypothetical head-to-head races between the president and some of the top Democratic candidates show Trump losing to each one. He majored in English, walked on to the heavyweight rowing team, where he served as captain his junior year, and played in punk rock bands at music halls around campus.