Juan Williams told viewers Tuesday on "Special Report with Bret Baier" that the latest Republican presidential primary races could signal the beginning of the end of Florida Sen. Marco Rubio’s bid.

"I think the big story is what's going on with Marco Rubio," the Fox News contributor said. "I just don't see any indication, in all these polls, that people are reacting well to him."

Rubio has managed to snag two wins so far this primary season, in Minnesota and in Puerto Rico, but despite a sharp push against frontrunner Donald Trump, he's failed to gain the traction with voters that his campaign had hoped for.

"We know he did well in Virginia last time, coming in very close, but this time, the argument that, you know what, Trump is a con artist, and Trump University is evidence of that kind of con, and that he's not to be trusted as a conservative— does not seem to be working at all in Michigan."

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