President Joe Biden called for tripling the tariffs on Chinese steel and aluminum, a policy proposal timed for his meeting with union workers in Pennsylvania on Wednesday.

While speaking before the United Steelworkers union, Biden will call upon U.S. Trade Representative Katherine Tai to triple the tariffs from their average level of 7.5%.

A White House fact sheet said the administration “recognizes growing concerns that unfair Chinese trade practices, including flooding the market with below-market-cost steel, are distorting the global shipbuilding market and eroding competition.”

The announcement is set to come during a presidential visit in a key swing state with a notable union and manufacturing base. Unions are typically supportive of higher tariffs.

Tariffs are billed by supporters as a means to narrow the trade deficit and support domestic manufacturing jobs. They’re also advertised as safeguarding the country’s supply chains, which, as the pandemic exposed, are often reliant on foreign nations for critical goods, such as medicines and certain critical minerals.