Sen. Rand Paul (R-Ky.) said the questions raised in the new book Clinton Cash should make people question the trustworthiness of Hillary Clinton. 

In a live studio interview on "Fox and Friends," Paul was asked why voters should be concerned about the money that flowed to the Clintons while Mrs. Clinton served as secretary of state. 

Paul responded that it's all about being able to trust the commander-in-chief.

"You have to trust your commander-in-chief that they wouldn't actually sell the country while they're the commander-in-chief. Secretary of State is an incredibly important position. She got to be on the approval of whether a uranium company was sold to Russia and she allowed it to happen while receiving money from the shareholders," said Paul. 

Steve Doocy asked Paul if he believes bribery occurred when it comes to Clinton's actions as secretary of state that were connected to Clinton Foundation donors.

The Republican presidential hopeful said Clinton's actions give the "appearance of impropriety," adding that the Constitution prohibits officials from accepting money from foreign countries.

Paul said there should "absolutely" be an investigation into the donations, explaining that he has expressed that opinion to his fellow senators.

Tune in tonight at 10p/1a ET as "Clinton Cash" author Peter Schweizer sits down with Sean Hannity.

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