With a new U.S. Trade Representative in place, the Trump administration this week launched the North American Free Trade Agreement (NAFTA) renegotiation process. The negotiations themselves will not begin before August 16, but the administration will need all that time to grapple with the difficult choices it faces.

The filing with Congress came with some hyperbole from Robert Lighthizer, the new USTR: "Today, President Trump fulfilled one of his key promises to the American people. For years, politicians have called for the renegotiation of this agreement, but President Trump is the first to follow through with that promise." Neither sentence is quite correct. The campaign promise was not to file for negotiations, but to rework NAFTA to resolve the complaints of American workers. That work remains to be done.

Then President-elect Donald Trump talks with workers during a visit to the Carrier factory in Indianapolis, Ind. (AP Photo/Evan Vucci)

Nor is this President Trump the first to follow through on a promise to negotiate a reworking of NAFTA. President Barack Obama did just that with the Trans-Pacific Partnership (TPP), which included both Mexico and Canada (and from which President Trump withdrew upon taking office).

Lest these seem like quibbles, the central challenge the Trump team will face is whether to try the sort of radical approach to NAFTA renegotiation that might appeal to the President's trade-skeptical base, or whether to adopt a more conventional tack. The latter would likely look very much like the discarded TPP.

These negotiations will be badly squeezed by an unforgiving timeline. At home, the pace will be governed by the dictates of the 2015 Trade Promotion Authority law. That is why 90 days must pass between this filing and the start of negotiations, for example. It is also constraining on the back end; even if the three NAFTA countries reached an agreement between August and December, the requirements of the law would place it before Congress in 2018, just as U.S. midterm elections got underway.