Democrats warn Trump on North Korea deal

The warning came days before Trump is set to meet with the North Korean leader Kim Jong Un at a summit in Singapore.

The principles would require North Korea to denuclearize and get rid of all biological and chemical weapons, end production and enrichment of nuclear materials, scrap its ballistic missile program and allow robust inspections. The agreement also would have to be permanent.

"If President Trump meets with Kim Jong Un and receives a deal that truly lives up to these principles, he will have made world a safer place," Senate Majority Leader Chuck Schumer told reporters on a conference call as the letter to Trump was released. "But if he tries to reach a deal with Kim Jong Un just for the sake of reaching a deal and the agreement fails to live up to principles we laid out, he will have been bested at negotiating table yet again."

The Democratic leader, a frequent and vocal Trump critic, said Democrats "hope" the talks will be successful but also said Trump must be willing to back away from the negotiating table if he can't secure a good deal.

Schumer added, "The President has broad discretion under existing sanctions law against North Korea. But if he uses that discretion to implement a ham-fisted deal, he should be ready for Democrats and hopefully Republicans to push back."

Schumer was joined on the call by the top Democrat on the Foreign Relations Committee, Sen. Bob Menendez of New Jersey, who said it's not clear yet if a deal with North Korea would be a treaty that would require Senate ratification but said at some point Congress would need to vote to relieve mandatory sanctions that are in place against North Korea.

But he warned that shouldn't happen for some time after it's verified that North Korea is abiding by an agreement.

"There would have to be at some point in time congressional action to ultimately do away with the mandatory sanctions but that would clearly require North Korea to be in the midst of compliance," Menendez said. "What we don't need to do is lift sanctions and then have North Korea -- as it has in the past through various administrations, both Democratic and Republican alike, then violate the essence of the agreement they came to. Reassembling sanctions is a much more difficult proposition."

Schumer said at this point Democrats are not pushing for legislation like the Iran Nuclear Agreement Review Act, which gave Congress the right to vote on the Iran nuclear deal that was negotiated by the Obama administration.

"If we think that President is veering off course, we would not hesitate to move," Schumer said. "Let's see where he's headed."

In addition to Schumer and Menendez, the letter to was signed by Sen. Dick Durbin of Illinois, Sen. Mark Warner of Virginia, Sen. Dianne Feinstein, of California, Sen. Patrick Leahy of Vermont and Sen. Sherrod Brown of Ohio.

The letter did not say anything about what should happen with US troops in South Korea, but Schumer and Menendez both said they didn't believe the troops should not leave anytime soon.

"To pull troops out at the beginning, before anything else is done, I think would be a big mistake and would be the wrong signal," Schumer said. "To our allies and to North Korea itself."

"Maybe in the longer term, if this actually can be successful and you have the full de-nuclearization, the giving up of chemical and biological weapons, and other elements of North Korea's nefarious activities, that maybe, working with the South Koreans, there might be a future when that might be possible," Menendez said. "But I don't imagine that future anytime in the near future."