President Trump’s team needs to convince China the United States has no plan for regime change to defuse the North Korean nuclear weapons crisis, according to a senior Senate Democrat.

“I don't believe China understands the U.S. objective in North Korea,” Maryland Sen. Ben Cardin, the top Democrat on the Foreign Relations Committee, told reporters Wednesday morning. “And I don't believe the United States understands China's objective in North Korea.”

That exhortation came amid a general statement of support for the Trump administration’s approach to handling North Korea, although Cardin had some criticism of Trump’s personal rhetoric. But he voiced a growing consensus that the problem lies with China’s reticence to put maximum pressure on the pariah regime.

“China, for whatever reasons, has not wanted to take sanctions to the point where they believe it could jeopardize the North Korean regime,” Cardin said. “And we've argued that if you start to impose those sanctions you'll get the attention of the North Korean regime and perhaps they'll change course.”

Trump’s team has been accused at various times of taking a confrontational approach, through sanctions, rather than trying diplomatic engagement to resolve the crisis. Cardin endorsed the broad U.S. strategy, while modifying the standard critique of the administration’s diplomatic efforts.

“Their view — and I support the view —is that the more we can isolate North Korea the better chance we have of (getting) diplomacy to work,” he said. “So, I think that's a consistent message but you have to have diplomacy. You just can't use sanctions, it's not going to work, because diplomacy also gets much stronger enforcement of sanctions.”

That’s a reference to the need to assure China that the United States doesn’t aspire to overthrow the North Korean regime. Secretary of State Rex Tillerson has tried to make that clear in public and private statements.

“We have reaffirmed our position towards North Korea, that what we are doing, we do not seek a regime change; we do not seek the collapse of the regime; we do not seek an accelerated reunification of the peninsula; we do not seek an excuse to send our military north of the 38th parallel,” Tillerson said in August.

But Cardin suggested some of Trump’s bellicose statements, rather than contributing to the U.S. ability to pressure North Korea, have undermined Tillerson’s efforts to assuage Chinese concerns.

“I think the national security team and Secretary Tillerson are on the same page,” Cardin said. “The president goes off script and he numerous times has undermined Secretary Tillerson's diplomacy [on] North Korea. There's no question that the president has at times made the passage towards diplomacy more challenging.”