Sen. Cory Gardner says North Korea's recent posture that contributed towards President Trump's decision to call off the June 12 summit in Singapore fits a "pattern of misbehavior." The promises of North Korean leader Kim Jong Un's family have been broken over the decades many times, and this is nothing new, the Colorado Republican told "CBS This Morning" on Friday.

A White House official told reporters Friday that the North Koreans failed to show up when the U.S. sent an advance team to Singapore, and the North Koreans hadn't been picking up the phone in recent days. Gardner said Kim's surprise meeting with Chinese President Xi Jinping, and possibly the "old guard" in North Korea who opposed a meeting with the U.S., may have also influenced Kim's posture towards the U.S. in recent days.

Gardner said what the U.S. is seeing is a struggle in Kim — a struggle between a peacemaker to bring his reclusive nation out of darkness, and between the propagandist. It looks like the propagandist won that debate, Gardner said. Gardner said he hopes the lingering questions of exactly why North Korea failed to communicate with the Americans will be answered.

But Gardner also said he hopes the U.S. and North Korea can get back to talking about denuclearization. Until then, Gardner said, the U.S. will "double down on our sanctions," and Congress is prepared to pass "additional sanctions."

Shortly after Gardner made those remarks, Mr. Trump tweeted a hopeful message about the possibility of peace on the Korean peninsula. On Thursday night, North Korea suggested it is willing to talk to the U.S. at any time, although some were skeptical of that claim, after years of North Korea breaking its word, and the North Koreans' recent failure to communicate with the U.S.