(Want to get this briefing by email? Here’s the sign-up.)

Good morning.

Here’s what you need to know:

Iran tweet echoes Trump’s threats to North Korea

• President Trump’s fiery warning to Tehran late Sunday resembled his aggressive stance toward North Korea last summer, which ultimately led to a summit meeting with that country’s leader, Kim Jong-un.

But Mr. Trump’s top advisers are more united in their opposition to engaging with Iran, and Tehran is less likely to bend to pressure. Experts and former officials who have negotiated with Iran say it would be difficult to replicate the diplomatic breakthrough with North Korea. We answered some questions about the latest face-off.

Mr. Trump’s threat also helped change the subject after a week of bad headlines about his meeting with President Vladimir Putin of Russia.