Most people retire by age 70. Next month, NATO turns 70. U.S. President Donald Trump has now been joined by Barry Posen, a so-called realist political scientist, in suggesting that it may be time for the alliance to retire as well.

To see if they are correct, let’s consider what international life might be like without NATO. There would be at least five set of consequences, all negative.

The most catastrophic impact of NATO’s retirement would be the risk of Russian aggression and miscalculation. Without a clear commitment to defend allied territory backed up by an American nuclear deterrent, President Vladimir Putin will certainly see opportunities to seize land he believes is Russian. He has already done this in Georgia and Ukraine. Had they not joined NATO, the Baltic states would probably already be occupied by Russian troops. Certainly Putin would also see an opportunity to seize more of Ukraine without the “shadow” of NATO to protect it.

History teaches us that major wars start when aggressive leaders miscalculate. German leader Adolf Hitler attacked Poland in 1939, believing that after then-British Prime Minister Neville Chamberlain’s Munich Agreement, England would be unlikely to respond. North Korea attacked South Korea in 1950 after the United States appeared to remove Seoul from its defensive perimeter. Iraqi leader Saddam Hussein invaded Kuwait in 1990, believing the United States had signaled that it would not respond.

In each case, miscalculation led to larger conflict.

Secondly, NATO’s retirement would also decrease American military reach, its political influence and its economic advantage. American bases throughout Europe not only provide for the defense of Europe — they bring the U.S. a continent closer to trouble spots that threaten vital American interests. Fighting the Islamic State group, clearly an American interest, would have been markedly more difficult without permanent U.S. bases in Europe and without the American-built coalition that included every NATO nation. Without NATO, the mutual security interests that underpin both U.S. bases and coalition operations would be undermined.

This extends to the economic realm. U.S. annual trade in goods and services with Europe exceeds $1 trillion, and U.S. total direct investment in Europe nears $3 trillion. These economic ties enhance U.S. prosperity and provide American jobs, but they require the degree of security now provided by NATO to endure.

NATO’s retirement would thirdly exacerbate divisions within Europe. NATO’s glue not only holds European militaries together — it provides the principal forum to discuss and coordinate security issues. The European Union is unlikely to substitute for NATO in this respect because it has no military structure, few capabilities and no superpower leadership to bring divergent views together.

Germany and France already seek a plan B should NATO collapse, but without the United Kingdom in the European Union, an all-European approach is likely to fail. The added insecurity of NATO’s collapse would also amplify current populist movements in Europe. The consequence could be renationalization of European militaries, a system that brought conflict to the 19th and early 20th centuries.

The fourth consequences of life without NATO would be global. American bilateral alliances in Asia would each be shaken to their core should NATO fail. America’s defense commitments there would become worthless. With China determined to claim a dominant position in Asia, the collapse of NATO would cause America’s Asian partners to seek accommodation with China, much as the Philippines is in the process of doing.

Trump’s decision to abandon the economic Trans-Pacific Partnership agreement has already given China new advantages in the region. Without credible American security commitments, there would be little to stop China from controlling the South China Sea and probably occupying Taiwan as well. Add to this equation the new footholds that China is building in central Asia, Africa and Europe: Abandoning NATO would help assure China’s competitive success.

The final impact of NATO’s retirement would be the near collapse of what has been called the “liberal international order.” This order consists of treaties, alliances, agreements, institutions and modes of behavior mostly created by the United States in an effort to safeguard democracies.

This order has kept relative peace in the trans-Atlantic space for seven decades. The Trump administration has begun to unravel elements of this order in the naive notion that they undercut American sovereignty. The entire European project is built on the edifice of this order. NATO is its principal keystone. Collapsing this edifice would undercut the multiple structures that have brought seven decades of peace and prosperity.

So the answer is clear. Life without NATO would be more dangerous and less prosperous. Russia and China would be the big winners at America’s expense. NATO simply can’t retire.

Yes, NATO has problems. It needs to be managed. But there is too much left to be done for retirement. And there is too much to lose if NATO fails.

Hans Binnendijk is a distinguished fellow at the Atlantic Council. He previously served as senior director for defense policy on the Clinton administration’s National Security Council.

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