President Trump's performance in key swing states will likely determine how down-ballot Republicans perform Tuesday night, Sen. Rand Paul, R-Ky., told "Your World" Monday.

Republicans are defending 23 of the 35 Senate seats up for grabs this year, a number that includes special elections in Arizona and Georgia. 

Paul predicted that his fellow Kentuckian, Senate Majority Leader Mitch McConnell, would be reelected to a seventh term, but admitted that "some of the others are up in the air."

"I think North Carolina and Iowa definitely go the way the president goes," Paul explained. "If President Trump wins North Carolina, I think [Sen. Thom] Tillis wins also. It's the same way with Iowa, and I think it's now looking like he's ahead.

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"But I think it's really impossible to make predictions since the polling has been so bad," he added. "I know of no one who has ever taken a poll. I don't answer my phone to anyone who I don't know who's calling. I don't know how you do polling in this day and age. Who takes a call from a random phone number?"

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Paul added that he believes there is something to the theory of the "shy" Trump voter being underrepresented in public polling, but added that it may be overstated.

"I was with the president in Arizona and we had 20,000 people at an airport. There is incredible enthusiasm, it's just hard to believe that that is all discounted and that the polls are right and he's being swamped," he said. "When you see that degree of enthusiasm, it's hard to believe that."