There are brief moments in history when a president can get big things done. Big things, like negotiating massive bilateral trade deals with economic rivals.

It takes a lot of harmonic convergence to set up such a window, but President Trump and his administration are in one as they negotiate with their counterparts in China.

Yet, success is no sure thing. Trump presides over a remarkably mercurial White House, often undercuts his own negotiators, and has inserted presidential pardons for international criminal prosecutions into these talks.

This is the man who has made much of his rapport with Chinese President Xi Jinping, but these personal international relationships he boasts of aren’t a guarantee of larger diplomatic success. Two failed summits with North Korean dictator Kim Jong Un and a disastrous press conference with Russian President Vladimir Putin spring to mind.

It invites the question: Will Trump squander this chance at a reset? If he does, America will have missed an opportunity. It will be a 'baseball through Bill Buckner’s legs' mistake. It will be years before another one comes again.

But now look back at the open windows that have lined up to make success possible. Trump has got a good domestic economy at his back to ensure that any bumps caused by this trade fight are relatively smooth. He’s buoyed by low unemployment, inflation, and a stock market that hasn’t spooked the shareholder class. He’s got political support to prosecute this reset thanks to Chinese import competition that has cost millions of American jobs and a business community weary of Chinese intellectual property theft, heavy-handed state economic participation, and creative Chinese interpretations of WTO liberalization rules.

What’s more, the other party at the negotiating table has plenty to deal with. After years of double-digit growth, China’s economy is returning to earth. Its massive state sector is retrenching, private investment is slowing, and the country’s population is aging.

Trump, meanwhile, has prepared the ground to make it more favorable to U.S. negotiating positions. The threat of lasting tariffs on most Chinese exports into the American market has made an impression; it has added billions in costs to Chinese businesses, and therefore has drawn the Chinese side to the bargaining table.

It’s no easy feat to persuade China’s economic managers to make structural reforms to a wildly successful mercantilist model that would result in more parity for U.S. trade interests. It remains to be seen how far a deal will go.

Most likely, it won’t go far enough. U.S. Trade Representative Robert Lighthizer has been working diligently through a prescribed set of issues with his Chinese counterparts. Based on some reports, they’ve been able to make more progress on some issues, such as forced technology transfers and IP theft, than on others, such as scaling back state-owned enterprises and improving enforcement mechanisms. Those unaddressed issues may be the most important results of what will eventually come out of this.

And still, the window of opportunity is open. The time to deal is now.

It’s time to demand more market access for American firms; firmly enforced intellectual property rights; enforced labor standards for Chinese workers; equivalent standards and enforcement for pollution controls; and escalated tariffs, should China fail to meet its obligations, rather than a lengthy and frustrating consultation process.

But what if, instead, Trump loses a fight with congressional Democrats, or has an executive order halted by the courts, or catches too much grief from Iowa soybean farmers over sales in this trade dispute, and decides a simply finished deal will serve him best? What will be left on the table when that window closes?

If the administration ends negotiations having sold a hill of beans to China and extracted few meaningful reforms, it will be a long time again before the U.S. can reset this trade relationship. History doesn’t remember missed opportunities fondly.

Scott Paul is president of the Alliance for American Manufacturing.