Taichung mayor Lu Shiu-yen is using her final months in office to warn about secret understandings between Washington and Beijing, and opposition city councillors are hitting back hard.

• Lu keeps telling the city council to watch what Trump and Xi may agree to "under the table" rather than in public.
• Her concern is sharpened by US Secretary of State Rubio saying openly that Washington cannot supply weapons to Taiwan.
• DPP councillors, led by Chen Yu-jung, say she has under three months left and is talking about things outside her job.
• They call her a political outsider in the making, noting her repeated calls for a national security meeting are being ignored in Taipei.
• The jab lands as DPP Taipei candidate Puma Shen drew national attention on a casual Taichung food stop, while Lu's warnings got little pickup.

Outlook: Expect Lu to keep raising Taiwan's security exposure in her last weeks, with the fight over whether she is posturing for a bigger national role only getting louder.