Sen. Rand Paul on Sunday pushed back against President Donald Trump's position on enacting tariffs to force the sale of Greenland to the United States, insisting that there is no emergency that makes that move necessary. 

The Kentucky Republican, appearing on NBC's "Meet the Press" in a bipartisan interview with Sen. Tim Kaine, D-Va., also called on Republicans to be "brave enough" to step forward and insist on checks and balances on the White House. 

"What I do isn't anti-Trump," Paul said. "My opinions are the same as they've been under President Biden, President Obama. I have not changed my opinions. Emergency powers are for emergencies. They should be short-lived. And we can't throw out all of the Constitution's rules on where taxes originate because someone declares an emergency."

And, he said, "There's no emergency with Greenland. That's ridiculous."

Earlier in the program, Treasury Secretary Scott Bessent said that Trump would be using his "emergency powers" to enact tariffs on Greenland and several other European countries pushing to block the transfer of the island to the United States. 

"Now we're declaring emergencies to prevent emergencies?" said Paul. "That would lead to endless emergencies and that's kind of where we are now.

"The tariff war, we've declared emergencies with 130 countries," he continued. "Does anyone really believe that's a valid use of emergencies?"

Paul and Kaine had launched a joint effort to limit Trump's ability to carry out further military action in Venezuela, which was defeated in the Senate after GOP Sens. Josh Hawley and Todd Young reversed their positions following threats by Trump against Paul and other Republican colleagues.

He told NBC on Sunday that the separation of powers goes back to the Constitutional Convention and the Federalist Papers, with the Founding Fathers determining that the power to go to war was too important to place in the hands of one person. 

"It's important not only because of Venezuela and what can or may still occur down there, but it's the predicate then for Greenland, for Cuba, for Colombia, for Iran, all of these other threats," said Paul. 

But it is up to Congress, not the president, to determine when to go to war, said Paul. 

"When we've been attacked, we've been pretty united," he said. "After Pearl Harbor, Congress was nearly unanimous; after 9/11, Congress was nearly unanimous, and that's the way it's supposed to work."

Kaine, meanwhile, said that there are several options with Greenland, including filing another War Powers Resolution or challenging Trump's imposition of tariffs. 

"Sen. Paul and I have worked together on similar tariff challenges in the past, and I think you will expect to see a number of senators join in an anti-tariff resolution filed right when we get back," said Kaine. 

Meanwhile, it is against the law for a president to suspend U.S. participation in NATO or to denounce it without congressional action, said Kaine. 

"These discussions, they're not helpful because they're pushing allies away from us rather than forging the stronger relationships with allies that we need," said Kaine. 

Paul said that he has heard of no Republican support for an invasion of Greenland, even from the GOP caucus's "most hawkish members."

But Trump, said Paul, "keeps rattling the cage" with such threats. 

"As far as trying to buy it peacefully, you don't get purchasers to come around by berating them and telling them you'll take it anyway," said Paul.