The “international community” has been tolerating this activity for years.

As America grew in the 1800s from a republic of a few millions, whose frontier stopped at the Mississippi, into a world power, there were constant collisions with the world’s greatest empire.

In 1812, we declared war on Britain, tried to invade Canada and got our Capitol burned. In 1818, Andrew Jackson, on an expedition into Spanish Florida to put down renegade Indians harassing Georgia, hanged two British subjects he had captured, creating a firestorm in Britain.

In 1838, we came close to war over Canada’s border with Maine; in 1846, over Canada’s border with the Oregon Territory.

After the Civil War, Fenians conducted forays into Canada to start a U.S.-British battle that might bring Ireland’s independence. In 1895, we clashed over the border between Venezuela and British Guiana.

War was avoided on each occasion, save 1812. Yet all carried the possibility of military conflict between the world’s rising power and its reigning power. Observing the pugnacity of 21st-century China, there appear to be parallels with the aggressiveness of 19th-century America.

China is now quarreling with India over borders. Beijing claims as her national territory the entire South and East China seas and all the islands, reefs and resources therein, dismissing the claims of half a dozen neighbors.

Beijing has bullied Japan and the Philippines and told the U.S. Navy to stay out of the Yellow Sea and Taiwan Strait.

In dealing with America, China has begun to exhibit an attitude that is at times contemptuous.

Here is a partial list of the targets of Chinese cyber-espionage:

The Wall Street Journal. The New York Times. Bloomberg. Google. Yahoo. Dow Chemical. Lockheed Martin. Northrop Grumman. Secretary of State Hillary Clinton. Chairman of the Joint Chiefs Adm. Mike Mullen. Los Alamos and Oak Ridge nuclear-weapons labs. The classified avionics of the F-35 fighter jet. The U.S. power grid.

U.S. computers are being hacked and secrets thieved, as Beijing steals the technology of our companies and manipulates her currency to minimize imports from the U.S.A. and maximize exports to the U.S.A.

“The international community cannot tolerate such activity from any country,” says National Security Adviser Tom Donilon.

Yet the “international community” has been tolerating this activity for years.

No one wants a war with China, and provocative though it is, China’s conduct does not justify a war that would be a calamity for both nations. But China’s behavior demands a reappraisal of our China policy over the past 20 years.

Consider what we have done for China. We granted her Most Favored Nation trade status, brought her into the World Trade Organization, threw open the world’s largest market to Chinese goods, encouraged U.S. companies to site plants there and allowed China to run trillions of dollars in trade surpluses at our expense.

In 2012, China’s trade surplus with the United States was over $300 billion, largest in history between any two nations.

What has China done with the wealth accumulated from those trade surpluses with the United States? How has she shown her gratitude?

She has used that wealth to lock up resources in Third World countries, build a world-class military, confront America’s friends in neighboring seas, engage in cyber-espionage, and thieve our national and corporate secrets. Is this the behavior of friends or partners?

And if the Chinese airily dismiss our protests, who can blame them?

For years they have engaged in cyber-espionage. They know we know it, and they have seen us back off calling them out. For years we have threatened to charge them with currency manipulation, and for years we have backed off.

If they have concluded we are more fearful of a confrontation than they, are they wrong? Other than fear or cowardice, what other explanation is there for our failure to stand up to China, when its behavior has been so egregious and insulting?

Does America fear facing down China because a political and economic collision with Beijing would entail an admission by the United States that our vision of a world of democratic nations all engaged in peaceful free trade under a rules-based regime was a willful act of self-delusion?

What China is about is as old as the history of man. She is a rising ethno-national state doing what such powers have always done: put their own interests ahead of all others, suppress ethnic minorities like Tibetans and Uighurs, and crush religious dissenters like Christians and Falun Gong.

There is no New World Order. Never was. The old demons — chauvinism and ethno-nationalism — are not ancient history. They are not extinct. They are with us forever. And America is not going to be able to deny reality much longer or put off facing up to what China is all about.

Given her current size and disposition, one day soon we are going to have to stop feeding the tiger. And start sanctioning it.

Patrick J. Buchanan is the author of “Suicide of a Superpower: Will America Survive to 2025?”