Nick Schifrin:

If you couldn't hear that, President Trump first told Putin as an aside, "Don't meddle in the election, please," and then pointed to Putin's staff and repeated the phrase.

The warnings are delivered with a grin, a contrast to the stone face that British Prime Minister Theresa May maintained in her greeting with Putin.

In response to questions about President Trump's tone, a senior administration official described efforts to improve local election infrastructure, enhance voter registration and ballot counting, and recognize foreign adversaries' manipulation of social media — quote — "From the beginning of his administration, President Trump has taken action to defend our election system from meddling and interference."

G20s are supposed to be calm conferences, but President Trump has made them less predictable. Before he left, he called into FOX Business to disparage the nearly 70-year-old treaty that pledges the U.S. to defend ally and G20 host Japan.