"It was so sad to watch," he told Powerhouse Politics podcast hosts Rick Klein and MaryAlice Parks. "You know we are essentially a nuisance power today. These nations that we're sitting with at the G-7 are just trying to survive meeting with Donald Trump, making arrangements without us and around us. And it's catastrophic in the long run to U.S. national security interests."
Murphy, D-Conn., points out that if Trump wanted to make his trade war with China a top priority, then he should have worked with the other G-7 countries to join his fight.
"It didn’t seem like he had the faintest interest in actually trying to make the agenda match up with his goals," he said.
Murphy has personally felt the tensions from the international summit. Russia denied a travel visa to him and his Republican colleague, Sen. Ron Johnson, R-Wisc., to attend as part of a congressional delegate visit of the Senate Foreign Relations Committee. The Russian Embassy has refused to comment, but issued a tweet accusing Johnson of being "russophobic."
"It's not shocking to me that they denied me a visa. I've been a tough critic of Russia's information warfare. They're meddling in the U.S. elections," Murphy said.
He is also upset because he says that channels of cooperation are being cut off. "I was going to Moscow to try to find some avenues of cooperation. You know, unfortunately it has fallen to members of the Foreign Relations Committee to keep relationships alive around the globe because this administration isn't interested in doing it. We have a totally dysfunctional relationship with Russia. And yet there are these important places where we have to cooperate whether it be Syria or Iran or counterterrorism."
Another headline that has swirled around Murphy is gun safety reform. Murphy has talked about how the Sandy Hook tragedy in 2014 in his home state of Connecticut changed his outlook as a senator, and as a father. Twenty children and six adults were killed in the elementary school shooting in Newtown. The mass shootings have continued, with the recent tragedies in Texas, and Ohio. Murphy said he talked directly to Trump about stricter background checks.
"I did speak with him shortly after the El Paso and Dayton shootings in which he made clear to me that he wanted to negotiate some expansion of background checks. And you know, even when there was a burst of reporting a couple of weeks ago, suggesting that the president had talked with the NRA and had reversed course, the White House immediately reached back out to me and said 'no ... don't believe those stories, we are sincere about trying to get something done on background checks. We want to build a process for negotiations.' And so we're in that process this week."
In a meeting with reporters on the White House driveway, White House senior counselor Kellyanne Conway confirmed that meetings on background checks were ongoing but that President Trump had not been briefed on the latest discussions.
Murphy said he’s not wildly optimistic. "I think the chances are still less than 50/50 that we end up with a significant background check expansion that the president supports and that can get 60 votes in the Senate. But we're talking in a more substantive way than we have ever done before during the Trump administration. I don't know that optimistic is the word, but I am absolutely willing to sit at the table with this administration on background checks."
Powerhouse Politics podcast is a weekly program that posts every Wednesday, and includes headliner interviews and in-depth looks at the people and events shaping U.S. politics. Powerhouse Politics podcast is hosted by ABC News Chief White House Correspondent Jonathan Karl and ABC News Political Director Rick Klein.