Agriculture Secretary Sonny Perdue talked about trade and the new U.S.-Mexico-Canada Agreement with his Canadian and Mexican counterparts at the USDA Agricultural Outlook Forum on Thursday. But a lingering problem remains over how and when the Trump administration would remove steel and aluminum tariffs against the country's closest trade partners. To protect domestic steel and aluminum manufacturers, President Donald Trump last March placed national security "Section 232" tariffs of 25% on imported steel and 10% on imported aluminum. Canada and Mexico immediately responded with retaliatory tariffs, including tariffs on some agricultural products. Despite getting a new trade agreement to replace NAFTA, the tariffs remain in place.Those steel and aluminum tariffs remain a thorn in getting the new USMCA trade deal ratified by Mexico and Canada. Perdue said he realizes U.S. farmers are getting hit with higher machinery costs because of steel and aluminum costs while commodity prices have declined or flattened. Perdue said, ideally, the tariffs will be lifted "sooner rather than later," but he had no specific knowledge on what's next.