Beijing's threat was vague but ominous — a warning from the Maritime Authority to stay out of a parcel of ocean in the Taiwan Strait.

"Live-fire drills to check Taiwan independence," declared the Global Times, a tabloid that often reflects China's most hawkish leadership voices.

Chinese commentators predicted a show of force involving the aircraft carrier Liaoning to "punish" the island's leaders who are "obstinately promoting 'Taiwan independence'."

Indeed, this week's manoeuvring was as much a propaganda exercise as a military one, firing off the kind of verbal shots the leadership here does more and more.

In the end, the aircraft carrier showed up, and Taiwan's Ministry of National Defence described the event as "routine artillery drills." Officials did, however, accuse China of "psychological warfare."

Taiwanese researcher Wu Jieh-min says similar efforts in the past have not scored any victories.

"When Beijing pushes too hard in its military threats on the people of Taiwan, they get a counter-reaction," says Wu from Academia Sinica, Taiwan's main national academy.

U.S. President Donald Trump, right, and Chinese President Xi Jinping early in 2017. This week's military exercise likely carried a message for the U.S.: don't try to use Taiwan as a bargaining chip to pressure China. (Andy Wong/Associated Press)

Long term studies done by the Election Study Centre at National Chengchi University in Taiwan show support for independence sat at 50 per cent in 2016, compared to 31 per cent in 2001. Meanwhile, backing for unification with the mainland dropped from 30 per cent to 17 per cent in that time. Just over a third of Taiwanese consistently preferred things to stay as they are.

For decades, Taiwan's self-governing democracy has angered and frustrated Communist leaders with its refusal to join the mainland and recognize Beijing's rule over what those leaders call One China. Beijing considers Taiwan nothing more than a rogue province that needs to be brought to heel.

Taiwan has never been a part of the People's Republic, not since it became a refuge for forces fighting Mao Zedong's Communists during the Chinese civil war. Instead, it has occupied a vague status as a de-facto state, armed and defended by Washington, but not formally recognized by the U.S.

Warships and fighter jets of Chinese People's Liberation Army (PLA) Navy take part in a military display in the South China Sea on April 12. (Reuters)

Soon after being elected, President Donald Trump seemed to be changing course, first by accepting an unprecedented direct phone call from Taiwanese President Tsai Ing-wen, then by questioning the One China concept.

"I don't know why we have to be bound by a One China policy," he told a Fox News interviewer, "unless we make a deal with China having to do with other things, including trade."

He drew diplomatic protests from Beijing.

Many countries, including Canada, have strong economic and cultural connections with Taiwan, but officially they avoid angering Beijing by sidestepping the issue of statehood with a formal acknowledgement of its One China policy.

Most Taiwanese leaders have been just as diplomatic, often issuing vague declarations to appease Beijing and never actually declaring independence. President Tsai has also stopped short of that declaration, despite being elected as the leader of a political party which considers Taiwan already independent.

Still, many in Beijing view her with suspicion and alarm, and the nationalist message from Chinese President Xi Jinping has sharpened public opinion.

"Every inch of our great motherland absolutely cannot and absolutely will not be separated from China," Xi said last month in his speech to the National People's Congress.

"Any actions and tricks to split China are doomed to failure and will meet with the people's condemnation and the punishment of history."

Xi has also moved to modernize China's armed forces, prompting people to believe "we could start a war toward Taiwan, and we have the ability to win it," according to users like "Sleepy Monkey" on China's internet.

It's adding to the pressure on Xi to "to resolve the Taiwanese issue finally," says Chu Shulong, a Taiwan expert at Beijing's Tsinghua University.

The Chinese public and even its elites "say we have endless trouble over Taiwan issues … big or small, every year. They say since we have the capacity to resolve the issue finally, why not use it?" says Chu.

More Taiwan visits

Despite Trump's questions about U.S. support for the One China policy, Washington did later reaffirm it. But that's still left Beijing wary, especially in light of other disagreements like trade, and after other U.S. moves that could lead to closer ties to Taiwan.

Last month, Congress unanimously passed the Taiwan Travel Act, which opens the door to more official visits to Taiwan — and at much higher levels — over China's protests. Washington is also planning to sell more than $1 billion worth of advanced weapons to Taipei.

So, observers say, this week's military exercise likely also carried a message for the United States: don't try to use Taiwan as a bargaining chip to pressure China.

"The signal is very clear," says Tao Wen Zhao, a senior researcher at the Institute of American studies in Beijing. "China will never let anyone separate Taiwan from the motherland. And China will take all necessary means to prevent that."