Whatever excuse they can find to generate big deportation numbers for the Malignant Narcissist in Chief to brag to his racist, fascist base. When they run out of the low hanging fruit of POC at the airport, they'll move on to actual citizens. It's about creating chaos and fear to consolidate more power, not actually making the USA great.
This is Putin getting his Puppet to weaken the USA to promote Putin's goals. Donvict is a Russian asset. A weak USA helps Russia and BRICS, especially for objectives like Ukraine. Other players, like the oligarchs, are also beholden to Putin.
'Tariff' isn't a beautiful word after all. It's as ugly as 'tax.'