A debate over Trump's warm relationship with New York mayor Zohran Mamdani frames a bigger worry: world leaders find Trump easy to flatter and manipulate.

• Trump has taken a liking to Mamdani, praising him publicly even though Mamdani is a left-wing critic.
• Mamdani won Trump over by handing him a flattering fake newspaper front page, then got Trump to free a detained Palestinian student that same afternoon.
• The pattern is the concern: Trump responds to flattery, so anyone who praises him can steer him — good or bad.
• Examples cited: Saudi Arabia plastered Trump's own tweets on billboards in 2017, and Netanyahu allegedly nudged him toward conflict with Iran.
• The newer risk raised is that foreign leaders can now influence Trump with money, not just praise.

Outlook: Expect more leaders, friendly and hostile, to keep using flattery and favors to get what they want from Trump.