WATCH: Lawrence O'Donnell Explains Why Trump's South Carolina Victory Was a Disaster

Donald Trump won a big victory in South Carolina last night. It was an important victory for him, not only because it helped to continue his momentum toward the Republican nomination, but because it came against Nikki Haley. 

Haley, who is the only opponent left running against the former Republican President, was the Governor of South Carolina for several years. Still, MSNBC's Lawrence O'Donnell says there are plenty of warning signs attached to Trump's big win. 

"These numbers are disastrous for Donald Trump," he began. "Disastrous. It’s the reason I mentioned the big forgotten number of South Carolina, which is Joe Biden getting 96%, okay? That’s what you’re supposed to get, alright, and Donald Trump’s not going to come close to that."

The host continued, "We don’t know what the result of this election is tonight, but it’s going to be a very substantial number. It could be a third of the vote. He’s going to leave that on the table, belonging to another candidate. All you need, all you need, is 5% of the 30%. We’re talking about a sliver."

Despite an embarrassing loss in her home state, Nikki Haley will be staying in the race. There are several things that could still derail Trump's run at this point and Haley is smart to stick around.