It's a ploy to shame the Sanctuary Cities into either "putting up" or "shutting up". The leaders of those cities know that if they accept Mr. Trump's offer, they will be putting a burden on their already-strained city budgets; and if they don't accept Mr. Trump's offer, they will be exposed as virtue-signalling hypocrites. It's lose-lose for the Sanctuary Cities.
Think "Poker", not "Chess".
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No love for Hamas, Hezbollah, Iranian Leadership, Islamic Jihad, other Islamic terrorist groups, OR their supporters and sympathizers.