Here are a few options, depending on where the title will be used, all maintaining a formal tone:
Option 1 (Direct and formal):
“Trump Administration Cites Brazil’s Misinformation Policies as Justification for 25% Tariffs”
Option 2 (More concise):
“U.S. Imposes 25% Tariffs on Brazil, Attributing Action to Disagreement Over Social Media Regulation”
Option 3 (Focusing on the diplomatic/policy aspect):
“Trump Administration Links New 25% Tariffs on Brazil to Controversies Regarding Social Media Content Moderation”
Recommendation: Option 1 is the most standard and professional choice for a news headline or formal report.