I’m pretty sure you’re missing the point. Like your link says, simply showing someone a weapon is not brandishing. There has to be an intent to intimidate. The video of this interaction makes it plainly obvious that there was no intention on the part of this politician to intimidate anyone.
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All that said, your link isn’t relevant to this situation anyway. The definition of brandishing is mentioned specifically in the context of someone who possesses a weapon “during and in relation to any crime of violence or drug trafficking crime”. (see 18 USC 924(c)(1) and (c)(4)). This guy was not in the middle of committing a crime of violence or drug trafficking, thus the brandishing definition does not apply.