Bernie Sanders on Monday night said he decided to run for president as a Democrat because of the media attention he would receive.
"Do you run as an independent? Do you run within the Democratic party? We concluded-- and I think it was absolutely the right decision, that, A) in terms of media coverage -- you have to run within the Democratic Party," the Vermont independent said at MSNBC's Democratic town hall in Columbus, Ohio.
The senator also said that the only way he could have launched a third-party bid was if he were a billionaire.
"If you're a billionaire, you can do that. I'm not a billionaire. So the structure of American politics today is such that I thought the right ethic was to run within the Democratic party," he said.
His comments came a day before critical primaries in five states, including Illinois, Florida and Ohio.
A CBS News battleground tracker poll released on Sunday found Clinton was leading in Ohio and Florida while Sanders had a slight edge in Illinois. Clinton, meanwhile, has a large overall lead with 1,222 delegates while Sanders has picked up 565. He or she must win 2,383 delegates in order to win the nomination.