Foreign Policy: In international diplomacy, credibility is all important. After 
taking out a Syrian chemical weapons base, President Trump now has 
credibility in spades. He'll need it in dealing with North Korea's nuclear threat.
Keen observers have noted that the missile attacks on the Syrian air base
 were launched as President Trump sat down last week to dinner with 
China's President Xi Jinping. No doubt Xi immediately recognized that
 this president, unlike the previous one, acts quickly to make sure bad
 situations don't get worse.
What does this have to do with North Korea? Plenty. Despite their at
 times rocky relationship, China is the totalitarian communist North
 Korean regime's main patron and protector, accounting for over half
 the North Korean nation's trade and much of its food and energy 
supplies. Strive as it does for self-sufficiency, without aid from China, 
North Korea would soon starve.
Even so, North Korean tyrant Kim Jong-un appears to be preparing for
 a sixth nuclear test, and has threatened the U.S. with a nuclear strike
 if it tries to interfere. Meanwhile, the U.S. has sent a Navy strike group 
to the region, with President Trump tweeting recently that North Korea
 is "looking for trouble" and that the U.S. will "solve the problem," whether
 China helps or not.
Knowing now that Trump means business, China seems to have reached
the end of its patience with its unpredictable client.
 international newspaper owned by the Chinese Communist Party,
warned that China's government has a "bottom line" and that if "the 
bottom line is touched, China will employ all means available
 including the military means to strike back."
The editorial went a step further, telling North Korea that it won't wait
 for the U.S. to do the dirty work, but "will launch attacks to (North Korea's)
 nuclear facilities on its own."
Since February, China has been curbing its trade with North Korea, and
 in recent days even turned away a fleet of North Korean merchant ships
 filled with coal, the impoverished nation's No. 1 export. So things are
 about to get ugly in North Korea's already-strapped economy.
Here in the U.S., we've been dealing with North Korea's provocations
 since the Korean War in the 1950s. Most Americans don't realize it,
 but that war never officially ended. There's only a truce.
The nuclear mess, however, is of recent vintage. Trump is dealing with
 the failures of previous U.S. administrations to end the threat, either
by twisting China's arm or by direct action. In the early 1990s, when
 North Korea threatened nuclear devastation and war with South
Korea, President Clinton sent former President Jimmy Carter to
 negotiate an end to the threat.
The Clinton White House proudly announced the "deal": an end to
North Korea's military nuclear program in exchange for billions of
dollars in aid and "peaceful" nuclear technology. Within just two
years, however, North Korea was cheating.
Hopes of getting China to help out with North Korea hit bottom last
 year, after China expressed open contempt for President Obama,
 even humiliating the president during last summer's G-20 economic
 summit by refusing to roll out a red carpet for him as it had for the
 other leaders and forcing Obama and National Security Advisor
Susan Rice to deplane from the rear of Air Force One. This only
emboldened North Korea's Kim.
"Kim knows that Xi is not about to further goals, like the denuclearization
 of North Korea, that (Obama) promotes, and so Pyongyang thinks
 it has a big green light in its quest to possess the world's most
 destructive weapons," wrote China expert Gordon Chang at the
time. That's what Obama's weakness in the face of China's open
 hostility achieved.
As for those who think the threat isn't real, they should think again.
 North Korea has focused intently on building a viable nuclear
threat for nearly three decades, and has made consistent progress
 both in building warheads and long-range missiles to deliver them.
A 2014 study by the U.S. based Institute for Science and International
 Security estimated that North Korea could have enough nuclear
 material for as many as 79 nuclear weapons by 2020. That's three
years away, folks.
As we noted before, China now has gotten the message: Trump isn't
 going to roll over like Obama did, and he means business. Xi learned
 this after being informed during a steak and seafood dinner that Trump
 had launched 59 Tomahawks at that chemical weapons base in
Syria — without asking Russia's permission, and after giving it just
 a short warning to get its troops out of harm's way.
That certainly explains China's sudden shift in tone toward North
 Korea to one of open hostility. China now knows there's a president
who not only understands U.S. interests in the region, but has explicitly
 told China that any trade deals between our two nations will depend
 on its cooperation in ending North Korea's nuclear threat.
Being nice and negotiating phony nuclear deals with North Korea
hasn't worked. The "six-party talks" on North Korea's nukes that
 have been going on since 2003 haven't worked either. By restoring
U.S. credibility, Trump has made China care about North Korea's
 nuclear threat in a way it never did before. It may be the best chance
 we have of avoiding a nuclear catastrophe from a nation ruled by a
 totalitarian sociopath.