The House of Representatives is preparing to vote on a bill to establish what’s called trade promotion authority or TPA. The bill may not sound like a showstopper, but the vote has America’s allies—and rivals—on the edge of their seats. If the House rejects TPA, it will signal to the world that America itself, not just President Obama, has grown weary of leadership. By contrast, if the House approves TPA, it will show that America is once again taking the lead.

Six years of a feckless foreign policy have eroded America’s credibility. Other countries don’t trust (or fear) the U.S. because they think the president is all talk and no action. Congress needs to show the world that even though the president doesn’t always follow through, it can still rely on America. And given the state of affairs, establishing TPA would be a real sign of seriousness.

Right now, the U.S. is negotiating two historic trade deals—one with countries on the Pacific Rim and the other with the European Union. One of the talks is already far along, but the countries involved have yet to put their best offers on the table— for a simple reason: Under the Constitution, the president can negotiate a trade deal, but Congress must approve it. And this division of power makes other countries think twice. They don’t want to make concessions to the administration only to see Congress rewrite the deal. So ever since the days of FDR, Congress has worked to establish TPA or something like it to beef up America’s leverage at the negotiating table.

What exactly is TPA? It’s a process for negotiating trade deals—one that puts Congress in the driver’s seat. Under TPA, when the president submits a deal, Congress agrees to give it an up-or-down vote, without amending it—but only on three conditions.

If the House rejects TPA, it will announce to the world that America is unreliable. But if the House approves TPA, it will underscore America’s commitment to a successful negotiation and reassert America’s leading role in world affairs.

First, the deal must address nearly 150 negotiating objectives set by Congress, like tearing down trade barriers to American products or putting up protections for U.S. intellectual property.

Second, the administration must consult regularly with Congress  during the negotiations and give every elected representative direct access to U.S. negotiators and the negotiating text. Third, the administration must make the text of the deal public for 60 days before the president can sign it so the American people can read it first. And in the end, Congress gets the final say. Whatever the proposed changes to U.S. law are, Congress must approve them.

Only TPA will reassure other countries they can trust the U.S., and so only TPA can give the U.S. the leverage it needs to win a fair deal for America’s workers. And sealing the deal will renew American leadership in the world. One of the easiest ways to extend American influence is to expand American trade. Opening up other countries’ markets to the U.S. binds them together—because when the U.S. grows, they grow. As a result, it’s in their interest to work with the U.S. for a greater, shared prosperity. For many countries, these trade deals demonstrate the value of American leadership: When the world plays by America’s rules, everybody benefits.

But other countries are trying to rewrite the rules without us. China is negotiating trade deals all over the world—deals that will let its products in and keep America’s out. So if the U.S. keeps standing still, it will fall behind. Between 2000 and 2010, for instance, the countries of East Asia completed 48 trade deals among themselves. And the U.S.? It negotiated just two of them. As a result, America’s share of East Asia’s imports fell by 42 percent. Less market share means less influence. So we as a country have to ask ourselves: Is China going to write the rules of the global economy, or is America?

Our allies in Asia are watching. Many of them are trying to decide for themselves what’s the best way forward: American-style free enterprise or Chinese-style crony-capitalism. These countries want to stand with the U.S., but before they place their bets, they need to know that America is strong and reliable. Establishing TPA will show them that the U.S. won’t leave them in the lurch.

TPA’s skeptics say they get all this, but don’t want to give more “authority” to President Obama because they don’t trust him. Well, neither do I. TPA doesn’t give the president authority. TPA holds the president accountable. The only way a deal gets an up-or-down vote is if it meets Congress’s stipulations. And the truth is, other countries won’t wait for the U.S. to elect a new president. The world is writing the rules of the global economy right now. Either we seize this opportunity, or we will lose it.

With so much at stake, if the House rejects TPA, it will announce to the world that America is unreliable. But if the House approves TPA, it will underscore America’s commitment to a successful negotiation and reassert America’s leading role in world affairs. After years of indecision, no puffed-up posture can enhance America’s stature. Only concrete actions can rebuild U.S. credibility. And number one on the to-do list is establishing TPA.

Republican Paul Ryan is Speaker of the U.S. House of Representatives. He represents Wisconsin's 1st Congressional District. Follow him on Twitter @SpeakerRyan.