If the United States were on good terms with Russian President Vlad Putin it might be easier to contain North Korean nuclear development or end it militarily. All President Putin needs to do is turn a blind eye to nuclear development technology and hardware transiting Russia to Kamchatka and on to North Korea to keep Kim Un’s program progressive. If the U.S.A. were on good terms with Russia President Putin might stay out of the way and not offer any support to North Korea. It might then be easier to persuade China to tighten sanctions on North Korea or to stand back if the U.S.A. chooses to pre-empt and terminate and possibility of north Korean nuclear attack on the U.S.A. or Japan.
One can see that the U.S. policy is something less than real politk and allows North Korea to develop ICBMs as well as nuclear warheads without real concern of sudden military determination from the United States to end the nuclear program and regime of Dictator Kim.
America is continuing Clinton-era policy to take as much from Russia as possible and assert a best-case scenario for Wall Street globalist regarding the value of historically Russian territory. The down side of that is lasting bad relations with Russia and liberality concerning North Korean nukes and ICBMs.