In conflicts from Ukraine to Taiwan, the West needs a strategy / Photo from UNIAN

One of the subtlest tools in the diplomatic kit is the concept of strategic ambiguity. In the right circumstances, it can achieve more foreign-policy goals than strategic clarity, even preventing war.

In the wrong situation, ambiguity can backfire and cause disaster. The question is which context currently applies to the standoffs in Ukraine and the Taiwan Strait, Andreas Kluth, a columnist for Bloomberg Opinion, wrote in an article.

In their own ways, China under President Xi Jinping and Russia under President Vladimir Putin have deftly been keeping their adversaries in check with deliberate ambiguity. By contrast, the West, from the U.S. to the European Union, has of late seemed ambiguous more by default than design. This must change.

Read alsoBiden wants to discuss Ukraine at meeting with Putin – adviserThe author offers to consider Putin. Having just rattled his sabers again near Ukraine, he's now withdrawing his forces from that country's borders. His purpose this time, it appears, was only to remind Kyiv and the West that he alone controls the pace of conflict escalation (and de-escalation) in the region, from Belarus to Georgia.

In his recent state address, Putin warned the West not to cross any "red lines," or it would suffer his "asymmetric" ferocity. Most tellingly, he added that "we ourselves will determine" where those red lines are. That's strategic ambiguity: We might strike you, but we won't tell you when or why, because we want you – Kyiv and the West – to keep guessing.

It is noted Ukrainian President Volodymyr Zelensky, by contrast, obviously yearns for strategic clarity, such as firm assurances from the West that it would defend Ukraine. Better yet, as he said this month, he'd like to take the next step toward membership in NATO, which would be the ultimate deterrence against Russia. But any move toward NATO membership would be exactly the kind of red line Putin was talking about. In that case, it would provoke, rather than deter, the very catastrophe that the U.S. and Europe are hoping to avoid: a full-scale invasion. That would force the West to decide whether or not to fight – and lose lives – for Ukraine, and above all whether it could even win that battle. So NATO, the U.S. and the European Union are remaining strategically ambiguous about how they'd respond to Russian belligerence.

Now consider the Taiwan Strait, arguably the archetype of successful strategic ambiguity. On paper the U.S. has always recognized only one China. But in 1979 it switched its diplomatic protocol from Taipei to Beijing, while also passing the Taiwan Relations Act. Masterfully, it says that "any effort to determine the future of Taiwan by other than peaceful means" would be "of grave concern to the United States."

Kluth says this deliberate ambiguity about whether the U.S. would repel a mainland attack arguably kept the peace for four decades. It forced the Chinese to fear a war with the American superpower. And it reminded Taipei that it didn't have a blank check to declare independence because the U.S. might not come to its aid.

The two examples show when strategic ambiguity works best. It's when the same message must simultaneously send different signals to two or more parties. In these examples, the West is telling, respectively, Moscow and Beijing not to attack, while reminding Kyiv and Taipei not to provoke. The resulting limbo is meant to avert war.

Read alsoFrance's Macron in phone talk presses Putin over Ukraine – mediaBut this only works as long as all sides feel that time is in their favor. China, for example, long felt it had to get militarily stronger before challenging the U.S. It also hoped to persuade the Taiwanese to reunify voluntarily, with growing economic cooperation and promises of political autonomy.

Both assumptions have changed. Beijing increasingly feels it could win a limited war against the U.S. And it fears that the island's population increasingly sees itself as distinct – in recent polls, a record 83% identify as Taiwanese as opposed to Chinese. Xi is also aware that his betrayal of Hong Kong's autonomy has convinced the Taiwanese that peaceful reunification would never be in their favor, the author said.

That's why a growing chorus in Washington is calling for replacing American strategic ambiguity in the Taiwan Strait with clarity. Richard Haass, the president of the Council on Foreign Relations, argues that the U.S. must make its willingness to defend Taiwan unambiguous to keep deterring China and prevent war. Maintaining ambiguity might instead scare America's other allies in the region, notably Japan and South Korea, into looking after their own security by building their own nuclear weapons.

In eastern Europe, such a line of reasoning is less straightforward. NATO allies such as Poland or the Baltic republics are also paying attention to the West's stance in Ukraine and similarly feel vulnerable toward Russia. But they won't start building their own nukes or seek alternative alliances. Moreover, if defending Taiwan is difficult, repelling a Russian attack on Ukraine is even harder. The West appears unsure how much its defense would be worth in lives.

Read alsoEU leaders to discuss Russia on May 25 summitAccording to Kluth, what's clear is that the choice between ambiguity and clarity is fraught with danger and a matter for the highest rung of statecraft. It's disconcerting when a U.S. president appears not to appreciate the concept of strategic ambiguity – in 2001, George W. Bush stated bluntly that he would "do whatever it takes" to defend Taiwan. It's equally worrisome when a president fails to grasp the proper deployment of strategic clarity. In 2012 Barack Obama warned Syrian dictator Bashar al-Assad not to cross the "red line" of using chemical weapons but then did nothing when Assad committed that atrocity the following year.

In East Asia, the case for switching from ambiguity to clarity is now strong. In eastern Europe, it remains weaker. But what worries me most is that the West's ambiguity in both regions increasingly seems desultory rather than strategic – the result of indecision as opposed to purpose.