Washington (CNN) The Trump administration can claim a genuine foreign policy win, marked by deft diplomacy on two continents, following the passage of the most punitive UN sanctions ever imposed against North Korea.

But it is impossible to say whether the $1 billion slap will slow the most serious national security crisis facing President Donald Trump: Pyongyang's race to top an intercontinental ballistic missile that could hit US soil with a nuclear warhead.

The President himself is not being slow to highlight his administration's success.

"After many years of failure,countries are coming together to finally address the dangers posed by North Korea. We must be tough & decisive!" Trump wrote in a tweet on Tuesday morning.

Washington and its allies will hope that the new assault on Pyongyang's already heavily sanctioned economy will change Kim Jong Un's calculations in the building nuclear showdown.

But North Korea's initial response, redoubling its refusal to discuss its nuclear and missile programs in any talks, underlined how intractable and dangerous the showdown is becoming for Trump, despite the incremental progress forged at the weekend.

China has supported tough sanctions on North Korea in the past, but this was the first time Beijing has signed onto sanctions passed specifically in response to an intercontinental ballistic missile test. On Monday, however, there were indications it now wants the onus put back on Washington and Seoul to defuse the crisis.

While Trump was celebrating his administration's work, Nikki Haley, the US envoy to the UN who piloted the sanctions through the Security Council, admitted that there are questions about the effectiveness of the sanctions and an approach that despite Trump's claims does not markedly differ from that of previous administrations.

"We don't know that they're going to work. but it's something we needed to do," Haley said on NBC's "Today" show on Tuesday.

"We said on Saturday, when we took the vote, this wasn't going to stop our North Korea problem. What this is going to do is send a strong and a united message."

The delicate diplomatic maneuvering was only a preview of the patience, nuance and strategic positioning needed to stop the showdown with Pyongyang spiraling out of control in the years to come, qualities that Trump himself has yet to show in abundance.

And while the administration secured the new sanctions with a team -- including national security adviser H.R. McMaster, Secretary of State Rex Tillerson, Haley, and career State Department and National Security Council officials -- it remains unclear whether the President will be content to allow that model of coordination to prevail in the coming months.

In June for instance, Trump caused mystification and a temporary blip in Asian regional tensions, when he tweeted: "While I greatly appreciate the efforts of President Xi & China to help with North Korea, it has not worked out. At least I know China tried!"

new CBS poll published Tuesday reflected public anxiety about North Korea -- and the President's capacity to deal with the crisis.

Nearly three-quarters of Americans are uneasy about the possibility of conflict with the Stalinist state, according to the survey. Sixty-one percent, meanwhile, were uneasy about Trump's ability to handle the situation with North Korea's nuclear program.

The push for sanctions, while the result of a coordinated administration effort, also followed a period of confusion and mixed diplomatic messages over North Korea policy.

While Tillerson had been raising the possibility of talks with Kim's government, Vice President Mike Pence has several times said Washington does not envisage negotiations. Late last month, CIA Director Mike Pompeo sent shockwaves through Asia by appearing to allude to the possibility of regime change in North Korea.

"This is high level diplomacy, and you have to be able to use all instruments of national power, in your approach to North Korea, so it makes perfect sense that US officials would be talking about diplomacy; sanctions; and the potential use of military force," said Abraham Denmark, former assistant secretary of defense for East Asia.

"The key though and the challenge, is making sure those messages are coordinated."

Trump, at least, was just happy to claim the victory.

"Just completed call with President Moon of South Korea. Very happy and impressed with 15-0 United Nations vote on North Korea sanctions," Trump wrote on Twitter on Sunday.

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Can it work?

The big question is whether the new restrictions against Pyongyang's exports of iron, coal, seafood, and access to international banks and trade, are fully implemented and actually work more effectively than the multiple rounds of previous sanctions imposed on the Stalinist regime over decades.

Tillerson said in Asia that he hoped the tough new approach would cause North Korea to reevaluate its options.

"We hope that this again, will ultimately result in the North Koreans coming to the conclusion to chose a different pathway, and when the conditions are right that we can sit down and have a dialogue around the future of North Korea."

Yet the regime's bitter response to the sanctions underlined the central conundrum of the crisis: North Korea's nuclear and missile programs, the key issue the US wants to broach, are exactly what it will not discuss.

"We will, under no circumstances, put the nukes and ballistic rockets on (the) negotiating table," North Korean Foreign Minister Ri Yong Ho said at an Asian regional summit in Manila.

The blast emphasized that for Kim's regime, the possession of nuclear and ballistic programs is a matter of existential survival, rather than a bargaining chip in talks, as it has been sometimes in the past.

Unless the new sanctions change that North Korean position, and do it soon, they will have little impact on the wider crisis, since US intelligence estimates that Pyongyang may have the capacity to deliver a nuclear weapon to the US mainland by early next year -- at a moment of truth for Trump.

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Can Trump pressure China?

Given that short time frame, it is also unclear whether these or other more punitive sanctions and deeper isolation for Pyongyang could sufficiently force Kim's hand.

"I don't think they will change the calculus that Kim Jong Un is working under," Gordon Chang, author of "Nuclear Showdown: North Korea Takes on the World," said on "The Lead with Jake Tapper."

"Until we stop this incremental approach, the North Koreans, they will just adjust. We have to go all in all at once, stop all of their income," Chang said, calling on Washington to impose economic costs on China to force Beijing to do more to rein in its recalcitrant ally.

Gary Samore, a former top nuclear negotiator for President Barack Obama said Beijing's role was "very significant" because it had joined sanctions to censure long-range missile tests.

"In, the past the Chinese have supported sanctions but only in response to nuclear tests," Samore said on CNN International. "Beijing has moved the bar now."

But there are also signs that China's assistance will not come gratis or is open-ended.

A commentary in the official China Daily Monday said that alongside a suspension of nuclear and missile activity by North Korea, Washington should agree to suspend military drills with South Korea, a demand the US side has repeatedly rejected.

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Risk of military action with North Korea

There is also no expectation that China's ultimate bottom line, the prevention of a scenario that could lead to a toppling of the Kim regime and a unified Korea leaning towards the US, has moderated, despite rising peninsular tensions.

Adding to rising tensions and strategic ambiguity is the possibility that Trump has concluded that a military option with Pyongyang may be preferable to an erratic, unpredictable foe casting a nuclear shadow over the United States.

All of Trump's recent predecessors considered the costs of a military exchange with Pyongyang, which could risk high civilian casualties in Seoul, unacceptable.

But none of those predecessors were faced with the imminent reality that North Korea could pose a direct threat to the US mainland.

Still, the blowback of any clash could be staggering -- hence the view of many observers that it would be unthinkable, even for Trump.

"I think, particularly a peremptory military operation against North Korea would be disastrous," former Director of National Intelligence James Clapper said on CNN's "New Day" on Monday.

"I believe the North Koreans would unleash all that artillery and rocketry they have lined up along the DMZ, and they would, as they have vowed many times, turn Seoul into a, quote, sea of fire."

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CLARIFICATION: This story has been updated to more accurately describe the sanctions that China agreed to for the first time.