Paul, who is seeking the Republican nomination for president, said on NBC's "Meet the Press" he would seek to abolish the income tax, bring home all 572,000 U.S. troops stationed around the word and end most foreign aid.

Paul said he would use steep spending cuts to offset the $1 trillion lost if the income tax were repealed.

"You need the income tax to police the world and run the welfare state. I want a constitutional size government," he said.

Paul said, if elected, he wouldn't send troops to help South Korea if North Korea invaded.

"Why should we, unless the Congress declared war?" he said.

Asked if the United States should intervene if Iran attacked Israel, Paul responded, "Well, they're not going to. That's like saying Iran is about to invade Mars. They don't have an army or navy or air force, and (the) Israelis have 300 nuclear weapons."