"This is a company that poses a national security threat," the Democrat from Virginia told CNBC on "Power Lunch" on Tuesday. "And if that threat is real, and we're going to listen to the intelligence community, this is a company that has violated American sanctions rules."
"For [Trump] to arbitrarily, depending on which day ... he wants to tweet, to decide whether this ought to have the kind of sanctions that the law implied or is he going to arbitrarily choose another route, I find that very dangerous. And not the way we want to send a message ... to a country like China."
On Tuesday, the president said his administration had not yet reached an agreement on whether to save ZTE. The company is currently under sanctions by the U.S. government.
At a press conference, Trump denied a Wall Street Journal report saying his administration had reached a tentative deal with Beijing. Still, moments later he said he may seek "a very large fine" against the company, up to $1.3 billion, and would like to see new management at ZTE — some of the framework outlined in the deal reported by the Journal.
Warner said many of his constituents are concerned that the president is "arbitrarily pick[ing] out a company" — one that has been the subject of security concerns, no less — and using it as a "trading chip."
The senator added that Trump has been "outfoxed" in negotiations with China, a country he said operates "on a different set of rules."
"It is the unanimous agreement of the intelligence community that they don't think we should be buying ZTE equipment," said Warner, who is also vice chairman of the Senate Intelligence Committee.
"The president, who seems to be not informed with what his own intelligence community's conclusions are, one day he says he's going to be tough, the next day he's talking about saving Chinese jobs, and now he's got this kind of in-the-middle position," Warner said. "I don't think that's how we ought to be operating."