The Trump administration is taking heat for striking a Syrian air base with Tomahawk missiles and hitting ISIS terrorists in Afghanistan with a MOAB, a conventional bomb so big that it has been dubbed the “Mother of All Bombs.” No doubt there are useful debates to be had about the pros and cons, both tactical and juridical. But one sure upside of these strikes is that they are a step toward restoring abroad the credibility of America as a power to be reckoned with.

That’s big, in ways that go way beyond the immediate battlefields. In a world grown dramatically more dangerous during President Obama’s eight years of appeasement and retreat, America badly and urgently needs to restore its lost credibility.

It would be great if diplomats could protect America, its allies and its interests with words alone. But in matters involving aggressive tyrannies, words don’t mean much unless they are backed up by military muscle and the credible willingness to use force. When that threat goes missing, predators take notice.

It’s also clear that when America backs down, the threats tend to compound. Predatory regimes tend to do business together, observe each other and learn from each other. When Russia snatches turf from a neighbor and gets away with it, that sends a message to China.

Beijing, with its interest in building artificial islands topped with military bases in the South China Sea, can see that it’s open season in Asia for accelerating such territorial grabs. When

North Korea conducts an illicit nuclear test and gets away with it, we can reasonably assume that Iran takes note.

For the world’s most dangerously ambitious and threatening tyrannies — from Russia to China, from North Korea to Iran — Obama’s neutering of American power over the past eight years created a host of opportunities that they eagerly seized. The sorry truth, given the character of these regimes, is that they would have been fools not to.

By the time Obama left office this January, America’s official words meant almost nothing. Take, for instance, Obama’s declaration in 2013 of a “red line” over the use of chemical weapons in Syria. That gave way to former Secretary of State John Kerry’s Lilliputian assurance that an American strike on Syria’s chemical weapons facilities would be “unbelievably small.” That turned into no strike at all, as Obama entrusted Russia with the supervision of its client despot in Damascus, President Bashar Assad — whose resignation Obama had called for, to no effect, two years earlier.

Small surprise that today Assad is still in power, still using chemical weapons, supported by the military muscle of President Vladimir Putin’s Russia — which after a post-Soviet hiatus and thanks in substantial part to Obama’s concessions has reemerged as a major player in the Middle East.

The rolling debacle in Syria has been just part of a ruinous global trajectory that began with Obama’s 2009 Russia “reset.” This included, in deference to Putin, America welshing on its promise of missile defense for Eastern Europe. When that became an issue in America’s 2012 presidential election campaign, Obama was caught on an open microphone promising Putin that after his reelection he’d have “more flexibility.”

Putin tested that flexibility in 2014 with appalling success, snatching Crimea from Ukraine. Obama protested, via words and sanctions, but did nothing persuasive enough to reverse Russia’s turf grab.

China, despite Obama’s vaunted “pivot” to Asia, has in recent years been jockeying with Japan, accelerating its island-building turf grabs in the South China Sea and conducting joint military maneuvers, on land and at sea, with Russia. In Beijing, Obama’s extended but feeble hand earned him an ignominious descent last September from the rear door of his presidential plane.

Iran endured heavy U.S. sanctions during Obama’s first term, but emerged from nuclear negotiations during his second term with a U.S.-blessed international deal, enshrined under auspices of the United Nations, that effectively re-opened Iran’s financial spigots while paving Iran’s path to the bomb. Obama accompanied that giveaway with a payout to the Tehran regime of $1.7 billion, wangled by way of a “settlement” of decades-old claims and shipped secretly to Iran in cash.

Predictably, Iran pocketed its gains, and carried on sponsoring terrorism, expanding its reach in the Middle East and testing ballistic missiles.

Which brings us to Iran’s longtime partner in missile development, North Korea. Pyongyang, with its totalitarian, dynastic Kim regime, has bedeviled American presidents, both Democratic and Republican, for decades. But after years of Obama’s passive policy of “strategic patience,” the threat posed by North Korea has soared.

Kim’s regime clearly feels free to brag up its prowess in developing deliverable nuclear weapons, threatening strikes on America and advertising its program to develop submarine-launched ballistic missiles — prototypes of which North Korea this Saturday paraded through the streets of Pyongyang. Pyongyang is now on the verge of a sixth nuclear test — four of its five tests to date having been conducted on Obama’s watch (in 2009, 2013 and two tests in 2016).

It can be tempting to diagnose Kim’s behavior as crazy. But whatever Kim’s personal pathologies, his calculus about America’s response — or lack thereof — has so far served him pretty well. While most of the 24 million people of North Korea bear the costs and suffer the miseries inflicted by Pyongyang’s totalitarian regime, Kim himself has accomplished the transition of power from his late father, Kim Jong Il, who died in 2012, and is building an arsenal his forebears could only dream of.

All this is part of the Obama legacy: the rising global agglomerate of emboldened tyrannies, with which Trump must now deal. Call it the Axis of Opportunism. To this scene, we must also factor in the jihadi non-state outfits which over the past eight years have made the most of the vacuums created by Obama’s various retreats. These include al Qaeda and the Taliban, both still going concerns; ISIS, which thrived when Obama withdrew U.S. troops from Iraq and for too long dismissed the dangers; and the terrorist-infested misery of today’s Libya, where Obama led from behind.

Obama’s policies invited the world’s most dangerous actors to conclude that America would no longer act in defense of the Free World, or of the rules and understandings that promote a modicum of peace. This is a path to conflict and carnage on a scale not seen since World War II. It is imperative that Trump find ways to change this calculus.

One need not love the use of ordnance to appreciate that with the unprecedented moves of hitting a Syrian air base with cruise missiles and dropping a MOAB to obliterate an ISIS nest in Afghanistan, he has sent an important message, in terms that predatory tyrants, from Moscow to Beijing to Tehran to Pyongyang, will understand.

Claudia Rosett is foreign-policy fellow with the Independent Women’s Forum, and blogs at Follow her on Twitter @CRosett.