John R. Kasich, a Republican, is governor of Ohio.

Does the United States still have the ability — or the will — to be the undisputed global leader, a role it has held since World War II? It’s a question to be answered soon by members of Congress as they approve or reject an initiative to give the United States expanded access to 11 countries that represent more than a quarter of the world’s trade, while leveling the playing field for U.S. workers and businesses.

How they vote on the Trans-Pacific Partnership (TPP) trade agreement will affect the course of the United States’ security, prosperity and global influence for the rest of the 21st century and determine whether we advance or retreat from our leadership role at a time of worldwide turmoil and uncertainty.

For me, the only common-sense direction is forward, because trade is the foundation of peace. Not only will the TPP promote peace and stability in the Asia-Pacific region, but also it will help maintain the United States’ essential strength in that hemisphere at a time of increased Chinese and Russian assertiveness.

Since World War II, the United States has maintained its global leadership by building alliances that helped us fulfill our most important responsibility — protecting Americans militarily and economically — and then sharing those responsibilities and protections with our allied democracies. “Leader of the Free World” was more than a motto we proudly wore in the Cold War and beyond; it was our pledge to the world’s democracies and repressed peoples alike that the United States would never let them down.

That’s why congressional approval of the TPP agreement is so essential to the United States’ continued leadership across the world, as well as to its security at home.

Don’t be fooled by divisive talk in the presidential campaign that the TPP is only a debate about trade. At its very core, this agreement is about making sure the United States continues to strengthen its essential alliances and is willing to sustain its standing as the global leader — something we have done for more than half a century.

While China and Russia — and dangerous client states such as North Korea and Iran — jockey to outmaneuver everyone else and gain a dominant hand for their global schemes, there are fast-growing, independent nations looking to partner with the United States and thereby bring their strategic, economic and political values into alignment with ours. That list begins with the initial TPP partners, but as many as 10 additional economies have expressed interest in joining.

The U.S. and 11 other nations have come up with a trade deal after years of negotiations. But what's in it, who hates it, and what happens next? (Gillian Brockell/The Washington Post)

The last thing we need is for these thriving markets to come to believe they can’t count on U.S. support, pushing them instead into economic and geopolitical relationships with China or Russia. In the event of our inaction and loss of resolve, the United States will surrender global leadership to our most aggressive rivals, dictators who have the most to gain: Vladimir Putin, Russia’s latter-day Stalin; and Xi Jinping, the most repressive Communist Chinese leader since Mao Zedong.

That’s why the TPP agreement enjoys full-throated, bipartisan support from America’s most respected national-security leaders, including former defense secretaries Robert Gates, Leon Panetta and Donald Rumsfeld and former secretaries of state Colin Powell, Madeleine Albright and James Baker.

They echo the stance of former president Ronald Reagan, who had it right when he said, “The freer the flow of world trade, the stronger the tides of human progress and peace among nations.” Reagan knew that when people trade together, it binds them together and promotes peace.

As a governor and former member of Congress who served for 18 years on the House Armed Services Committee, I am convinced that the TPP agreement will strengthen those alliances, helping attain the peace and progress Reagan spoke of and achieved through his own insistence on U.S. leadership and resolve.

We cannot turn our backs on that legacy or abandon this opportunity, because expanding trade is about more than growing our economy; it’s also about ensuring our national security and asserting the United States’ willingness to stand tall against those who wish us ill.

It’s been more than 250 days since these 12 countries came together to sign the TPP agreement. As each new day passes, we should be concerned that the world’s doubts grow stronger about the United States’ willingness and ability to continue its historic role. It’s time for members of Congress to put aside partisan politics, resolve their differences and ratify the deal. Their vote will send a message to the world that we are the global leader, today and forever.