Sen. Ted Cruz (R-Texas) pushed back this morning against the idea that his flat tax plan - which includes the abolishment of the IRS - is unrealistic.

Cruz was asked by Stuart Varney about the argument that abolishing the IRS is seen as a "pie in the sky" proposal. 

Cruz pointed back to Ronald Reagan, saying he accomplished his tax cut plan by making the case successfully to the American people. 

He said if he wins the presidency, he'll have a "mandate" to implement these proposals.  

Cruz said under his plan, those who make over $36,000 a year would pay a 10 percent flat tax, while those under that total would pay no taxes.

All businesses, from giant corporations to small family operations, would pay a 16 percent flat tax. 

By doing this, Cruz said he could eliminate payroll taxes, the death tax, the alternative minimum tax and all ObamaCare taxes. 

"For a family of four, for an average American, you can fill out your taxes on a postcard or an iPhone app and we will be able to abolish the IRS because it'll be a simple flat tax for everyone," said Cruz. 

Watch the interview above, including some amusing thoughts from Judge Napolitano. 

Don't miss the next Republican presidential debate on Fox Business Network, Tuesday November 10th at 9p ET.