Republican Sen. Rand Paul on Thursday defended President Trump's July 25 call with Ukraine President asking Volodymyr Zelensky to investigate the Bidens, declining to say whether such a request was wrong. The senator gave his comments as the White House has said it will not comply with the House's impeachment probe.

Paul, appearing on "CBS This Morning," declined to give a "yes" or "no" answer when asked in various ways whether Mr. Trump was in the wrong to ask a foreign leader to investigate a political rival. The senator instead said the American people want everyone to be treated fairly and that Mr. Trump simply has a more "direct" way of making requests.

"Is it wrong, or isn't it?" asked "CBS This Morning" co-host Anthony Mason, of the president's request to investigate the Bidens. "Well the — no I think it's not incorrect or wrong to," Paul responded. "It's OK for the president to be—" Mason questioned. "Well, no, let me finish," Paul said. "What I would say is that aid that we give to other countries should be contingent upon behavior. And whether or not we should have Ukraine trying to eradicate corruption, yes." "This was specifically about Mr. Biden," Mason interjected. Well I don't know, ask the American people if they think $50,000—" Paul said. "I'm asking you, you're a senator," Mason said. "Well I know, but ask the American people do you think $50,000 a month that Hunter Biden was getting might have been corrupt?" Paul said. "You were running for president in 2016, would you have done this if you were elected?" co-host Tony Dokoupil said. "I think everybody has different ways that they would approach things," Paul said. "You sir, you," Dokoupil said. "Well the thing is, now we're getting down to whether or not it's personality and how he interacted in a phone call. Do you impeach people because he has a more direct way of approaching?" Paul said. "It's not a question of impeachment. It's a question of, is it right or wrong to ask a foreign leader to ask in an election? With, by the way nearly $400 million in aid hanging over his head?" Mason said. "I guess the thing is, would you say we can't investigate corruption if they happen to be a political figure?" Paul said.

Paul also defended the president's decision to pull troops from northern Syria, a move that Mr. Trump's critics and even many of his staunchest supporters say endangers Kurdish allies and threatens to undo progress in the battle against ISIS.

Paul said the president from the beginning said the goal was to defeat ISIS, and Paul thinks the U.S. has achieved that goal. Paul said the U.S. may have even encouraged peace talks between the Kurds and Turkey.

"What kind of war do you go to with 50 soldiers?" Paul said, suggesting the number of troops the U.S. was keeping in the region could do little good.

"I think it's a smart thing to do," Paul added of the president's decision.

Paul said he has not spoken with Mr. Trump since the president announced the troop withdrawal.

Paul has authored a book, "The Case Against Socialism," in which he argues an expanded welfare state will cripple the economy built on capitalism. The working class and middle-class bear a lot of the weight in other countries.

"The big lie you're getting from the left in our country is oh, the rich people pay for it," he said.