Investors hunkered down Thursday, as signals from China and the United States suggested that both nations were girding for a long-term trade fight.

In Washington, the Trump administration announced a substantial aid package for farmers, in an effort to cushion the blow as China buys fewer American agricultural products in retaliation for tariffs. In Beijing, President Xi Jinping has tried to rally the nation by invoking key moments in Chinese Communist Party history to signal hardship ahead.

For stock investors, that has meant adjusting expectations to a conflict with no end in sight. Already, existing tariffs on each country’s exports have been raised, and the White House is weighing whether to expand the tariffs to include consumer products — from shoes to electronics — that currently don’t face levies.

Worries about the cost of this battle, to global growth, corporate profits and American consumers, sent stocks down across the globe on Thursday.