In this image made from video provided by Host Broadcaster Mediacorp Pte Ltd, U.S. President Donald Trump and North Korean leader Kim Jong Un shake hands ahead of their meeting at Capella Hotel in Singapore, Tuesday, June 12, 2018. (Host Broadcaster Mediacorp Pte Ltd via AP)

WASHINGTON — Republicans in Congress expressed uncharacteristic skepticism on Tuesday about President Donald Trump's claim that his summit with Kim Jong Un opened "a new history," noting that the first-ever meeting between U.S. and North Korean leaders yielded few tangible commitments toward denuclearization, and a significant American concession.

"Should be skeptical of any deal with #KJU," Sen. Marco Rubio of Florida tweeted, sounding a common note about Kim Jong Un.

"Limits to future strategic weapons instead of eliminating current program not an acceptable outcome. Hope I'm wrong but still believe they will never give up nukes & ICBM's unless (they) believe failure to do so triggers regime ending reaction."

Tennessee politicians react

"Last night, President Trump exemplified what it means to be a leader, becoming the first sitting president of the United States to meet with a North Korean head of state. I applaud the President for taking this courageous step and I am hopeful that despite North Korea's history of deception, this summit marks the beginning of a new era of relations between North Korea and the United States. As Secretary of State Mike Pompeo leads U.S. negotiators in follow-up discussions with their North Korea counterparts, incorporating the knowledge of experts from the Department of Energy and the National Nuclear Security Administration will be of paramount importance. Much of this expertise resides in Oak Ridge, Tennessee and I look forward to continuing to support NNSA's nonproliferation mission. While there is still a great amount of work that lies ahead, this summit was a tremendous first step and marked yet another milestone for the Trump Administration." — Congressman Chuck Fleischmann

"While I am glad the president and Kim Jong Un were able to meet, it is difficult to determine what of concrete nature has occurred. I look forward to having Secretary Pompeo before our committee soon to share his insights and look forward to carrying out our oversight responsibilities." — U.S. Senator Bob Corker

While Trump sought to portray the meeting in Singapore as a personal victory, skeptics passing judgment in social media and on cable television said North Korea's Kim was the bigger winner simply by getting a U.S. president to share the world stage with him, something prior North Korea leaders — his father and grandfather — had not been able to extract because of their repressive records and broken promises.

Trump's typically obsequious GOP allies quickly expressed doubts that Kim would keep his vague promises this time as well, and objected that the president had so soon agreed to suspend longstanding U.S.-South Korea military exercises in the region.

Sen. David Perdue (R-Ga.), typically an ardent supporter of the president, said he was "surprised" and "troubled" by Trump's decision to end military exercises. "Coordination with the South Korean military is absolutely critical," he told reporters at the Capitol.

Republicans also took issue with Trump's effusive praise for Kim. Among other compliments, the president called Kim "very talented" in running his country — a nation that the United Nations, human rights groups and past American administrations have characterized as a prison state.

Rubio, in another tweet, countered that while Trump was "trying to butter him up to get a good deal," Kim "is NOT a talented guy. He inherited the family business from his dad & grandfather. He is a total weirdo who would not be elected assistant dog catcher in any democracy."

Sen. Lindsey Graham (R-S.C.), who has forged a working relationship with the president after initial feuding, was more positive. He voiced optimism that Trump could get Kim to follow through on his promise to end his country's nuclear weapons program, though Graham acknowledged that the details still to be negotiated will be more telling than the photo-ops and brief communique in Singapore.

"Here's what I would tell President Trump: I stand with you but anything you negotiate with North Korea will have to come to the Congress for our approval," Graham said on NBC's "Today" show.

"Details matter," Graham added. "But I'm hopeful. I think he has convinced Kim Jong Un that he's better off giving up his nuclear weapons than he is keeping them."

Influential conservatives outside of Congress generally were more pessimistic, and blunt about it, in media outlets.

"Pre-emptive celebration of a Great Victory by the president is sheer partisan hackery," tweeted author Ben Shapiro. "Nothing has been accomplished yet. Perhaps it will be. Celebrate then."

Bruce Klingner, the longtime CIA lead on North Korea and now a senior fellow at the conservative Heritage Foundation, tweeted: "This is very disappointing."

He wrote that the four main points in the Trump-Kim communique were the same as in agreements that past U.S. administrations brokered "in a stronger, more encompassing way" than Trump had. The provision on North Korea's denuclearization "is weaker," Kingner wrote, and the two leaders made no mention of verification procedures or North Korea's human rights abuses.

Sen. Cory Gardner of Colorado, chairman of Senate Republicans' campaign committee, issued a statement that praised the administration for engaging with North Korea while echoing those who remained doubtful of Kim's word.

"Until such time as North Korea takes concrete steps to denuclearize, our policy should be to continue the maximum pressure campaign," Gardner wrote, though Trump has said he is no longer using the term "maximum pressure" for sanctions against Pyongyang, in deference to Kim.

"The complete, verifiable, and irreversible denuclearization of the Korean Peninsula, as enshrined in US law and multiple United Nations Security Council Resolutions, must be the only goal of US engagement with North Korea," Gardner added.