FILE - Soldiers prepare to destroy a ballistic SS-19 missile in the yard of the largest former Soviet military rocket base in Vakulenchuk, Ukraine, Dec. 24, 1997. Trump administration officials say the U.S. sees value in the New START arms control a...
FILE - Soldiers prepare to destroy a ballistic SS-19 missile in the yard of the largest former Soviet military rocket base in Vakulenchuk, Ukraine, Dec. 24, 1997. Trump administration officials say the U.S. sees value in the New START arms control a...

CAPITOL HILL - Russian arms control violations and other malign activities are eroding the confidence and trust required to extend a critical nuclear agreement between Washington and Moscow that expires in 2021, U.S. officials told lawmakers on Tuesday.

"Russia continues to violate a series of arms control obligations that undermine the trust of the United States can place in treaties, including some that have served U.S. and allied security interests for years," Under Secretary of State for Arms Control Andrea Thomson said in testimony before the Senate Foreign Relations Committee.

"The bottom line is that arms control with Russia is troubled because the Russian Federation apparently believes it need only abide by the agreements that suit it," Deputy Under Secretary of Defense for Policy David Trachtenberg said.

Negotiated by the former Obama administration, the New START treaty has limited America's and Russia's strategic nuclear arsenals since going into effect in 2011. U.S. officials said discussions have been held with their Russian counterparts on possibly extending or renegotiating the 10-year pact, but that Russian violations of an earlier accord between the United States and the former Soviet Union are a sticking point.

"Russia has persisted in its violation of the INF [Intermediate-Range Nuclear Forces] treaty through its … ground missile program," Thompson said. "This administration has utilized diplomatic, economic, and military measures to pressure Russia to return to compliance. The lack of any meaningful steps by Russia to do so diminishes our hope that it wants to preserve the INF treaty."

Russia also accuses the United States of INF treaty violations. By contrast, both sides are believed to be adhering to New START's provisions.

Asked whether the United States would extend New START, renegotiate the pact, or allow it to expire, Thompson said, "No decision has been made at this time."

FILE - U.S. Senator James Risch.
FILE - Senate Energy and Natural Resources Committee member Sen. James Risch, R-Idaho listens during the committee's markup hearing on energy legislation, June 17, 2009.

Republican Senator James Risch of Idaho applauded the Trump administration's skepticism about Moscow's intentions and apparent willingness to walk away from New START.

"Trying to negotiate with people who aren't negotiating in good faith is a problem," Risch said. "They [Russian officials] are serial cheaters, they're serial liars, and you have to look at the other things they are doing in the world to judge what kind of a mind these people have as far as whether they are acting in good faith."

But several Democrats argued New START provides a core benefit even if Moscow is violating other treaties.

"New START gives us the opportunity to do the inspections [of Russian facilities] … This is extremely valuable," Senator Ben Cardin of Maryland said. "We know North Korea has a nuclear program, but we don't know the specifics because we don't have inspections [of North Korean nuclear sites]. We don't have eyes on the ground."

Democratic U.S. Sen. Bob Menendez leaves the feder
Democratic U.S. Sen. Bob Menendez leaves the federal courthouse in Newark, New Jersey, Nov. 13, 2017.

The committee's top Democrat, Bob Menendez of New Jersey, echoed the concern.

"Would withdrawing or walking away from an agreement strengthen our hand or ultimately leave us without a seat at the table, without insight into our adversary's stockpile? Safer or less secure?" Menendez asked.

Trachtenberg declined to speculate, but said, "We are taking a deliberate approach to our assessment of all of these treaties, including the New Start treaty. I don't see this as a rush to judgment on the part of the administration."

The deputy under secretary of defense added, "Any decision on extending the treaty will and should be based on a realistic assessment of whether the New Start treaty remains in our national security interest in light of overall Russian arms control behavior."

U.S. President Donald Trump, left, and Russian Pre
U.S. President Donald Trump, left, and Russian President Vladimir Putin arrive for a one-on-one-meeting at the Presidential Palace in Helsinki, Finland, July 16, 2018.

Several senators noted that U.S. lawmakers still don't know details of a private meeting in July between President Donald Trump and Russian President Vladimir Putin in Helsinki.

"We remain largely in the dark as to what the two leaders discussed or agreed to during their two hour closed session," Menendez said. "We do know that the Russian Ambassador to the United States Anatoly Antonov told reporters that important verbal agreements were reached at the Helsinki summit on arms control issues."

Menendez added, "Has the president reached key decisions with Russia on arms control treaties? If so, why hasn't Congress been informed?"

Thompson said she could provide no details of the Helsinki encounter, except that arms control was a topic of conversation.