War dominates the news these days, from the conflict between Russia and Ukraine to the battles splitting the Israelis and Palestinians. Last weekend, as Pope Francis marked the centenary of the First World War, he offered a bleak observation: Perhaps one can speak of a third war, one fought piecemeal, with crimes, massacres, destruction.

He meant that were possibly living through a slow-motion Third World War.

This wasnt the legacy President Obama had envisioned for himself. He was elected to the White House on a promise to improve Americas image and reduce its military entanglements. Last week, however, he felt compelled to go on television and plead for aggressive strikes against the Islamic Republic.

Sometimes even peacenik presidents must fight.

Yet, I believe President Obama should stick to a few of his original principles. In the final years of his presidency, he has a unique opportunity to leave behind a world thats primed for peace. To achieve this goal, he must push harder than ever before for free tradeand in particular, for the completion and passage of the Trans-Pacific Partnership (TPP), an agreement that would link the United States with a group of nations around the Pacific Rim.

When countries go to war, they need peace treaties, not trade agreements. Tariff reductions wont settle the differences between Russia and Ukraine. Export quotas arent the secret source of Middle Eastern turmoil.

The miracle of free trade is something else entirely: It can stop the fighting before it starts.

Nations that trade goods and services dont shoot bullets or fire missiles at each other. There are plenty of exceptions to this truism, of course, but its also a sturdy rule of thumband one that ought to guide President Obamas diplomacy during his administrations home stretch.

Last week, U.S. trade negotiators returned home from Hanoi, where they participated in the latest round of TPP talks. They claimed to make progress, meaning that with a few more successful meetings, they could strike a deal that will connect the economies of a dozen countries whose annual economic output approaches $30 trillion.

This would open new markets for U.S.-made goods and services, fueling growth and creating jobs within our borders.

As a farmer, I have a big stake in trade. I live in landlocked Iowa, close to the geographic middle of the United States, but my familys wellbeing depends on customers in other countries. We export about a third of our corn and about half of our soybeans.

So how would TPP promote peace? Lets remember the Second World War, the one sandwiched by the older and newer conflicts mentioned by the pope a few days ago. Its Pacific theater pitted the United States and its allies against Japanin other words, it divided the countries that TPP now brings together. A generation later, the United States fought in Vietnam, another participant in TPP talks.

In the 21st century, it may be hard to imagine a new conflict between the United States and Japan or Vietnam. Yet back when our soldiers were dying on the islands of the Pacific and in the jungles of Indochina, it was probably difficult to conceive of the partnerships we enjoy today.

If geopolitics teaches us anything, its that theres no such thing as permanent friends or everlasting enemies.

This is where TPP fits in. Trade produces incentives to solve quarrels before they explode into something worse.

Stronger economic connections among countries that ring the Pacific Ocean will create the conditions for more peace. That will be especially true if China ever joins the TPPan expansion that wont happen in the near term, but could happen in due course, as TPPs economic benefits become apparent.

We wont ever live in a world without conflict. The actions we take today, however, will shape the world our children and grandchildren inherit. With the right mix of determination and diplomacy, we can make their situation better than it would be otherwise.

So in his last two years, President Obama may need to wage a war he didnt anticipateand he should also use free trade to bring us a peace well welcome.

Bill Horan grows corn, soybeans and other grains with his brother on a family farm based in North Central Iowa. Bill volunteers as a board member and serves as Chairman for Truth About Trade & Technology (www.truthabouttrade.org).

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