Few details about President Donald Trump’s global trade policy are available hours before an announcement is set to land.

Trump is scheduled to unveil the new tariff policy at 4 p.m. in the White House’s Rose Garden. Multiple news outlets have in recent days reported that several options are still on the table, but the president has said he has already settled on one choice.

In the meantime, here’s what we do know.

The Policy Will Be Aimed At Making Trade ‘Reciprocal’

The latest tariff policy will be aimed at creating fairer trade relationships, Trump has said.

“The United States is one of the most open economies in the world, yet our trading partners keep their markets closed to our exports,” the White House said in February. “This lack of reciprocity is unfair and contributes to our large and persistent annual trade deficit.”

Two options suggested by the president involve imposing tariffs on other countries that have high import taxes on U.S. goods. In one, a blanket 20% tariff would be applied to most goods coming into the country.

The other option is tailoring the tariffs based on how much a country taxes U.S. goods. Under that option, the tariff could be applied to all goods from a particular country at a flat rate or applied tit-for-tat on a goods basis.

Whatever The Policy Is, It Will Likely Be Effective Immediately

In recent months, the president has laid out a tariff plan and set a deadline for implementing the policy further in the future. That may not be the case this time. White House Press Secretary Karoline Leavitt on Tuesday said the policies would be immediately effective.

“My understanding is that the tariff announcement will come tomorrow; they will be effective immediately. The president has been teasing this for quite some time, as you know,” Leavitt said. “He’s been talking about it for a while and as a result, you’ve seen these companies make commitments to investing right here in the United States.”

Trading Partners Are Expected To Retaliate

Even before the tariffs were announced, other countries were bracing themselves for the latest development in Trump’s trade war.

Reciprocal tariffs, in whatever form they’re imposed, are just the latest tariff that Trump has implemented. Leaders in major trading partners such as Canada and Mexico have been back and forth with Trump, resulting in on-again and off-again tariffs on their goods.

Canadian Prime Minister Mark Carney said his country would retaliate if new tariffs were put into place. “We will not disadvantage Canadian producers and Canadian workers relative to American workers,” Carney reportedly said. 

And it’s not just partners that have been previously targeted that are considering responses.

“We do not necessarily want to retaliate,” European Commission President Ursula von der Leyen reportedly said on Tuesday. “If necessary, we have a strong plan to retaliate and will use it.”