WASHINGTON, D.C. (NEXSTAR) — It’s the trade deal that could make or break many American businesses — from farmers to auto manufacturers. On Tuesday, lawmakers are digging into the United States-Mexico-Canada Agreement for the first time.

Right from the start, U.S. Trade Representative Robert Lighthizer was in full defense mode trying to sell the USMCA to a room of mostly skeptical senators.

But Oregon Democrat Ron Wyden says he’s not buying it. He says the USCMA, as written, isn’t strong enough.

“There is a lot of work that has been done but we are not there yet,” said Democratic Senator Debbie Stabenow. “And specifically on enforcement and labor and the environment and also medicines and access to medicines.”

Enforcement isn’t the only concern Democrats say they want to see addressed before they vote to ratify the trade deal.

Lighthizer says both Mexico and Canada are also on track to approve the agreement this summer.