There's a lot of concern that Trump will restart the tariffs of his prior administration, but isn't it far harder now to enforce tariffs than in 2016?

Everyone's economy sucks, so there's far more incentive to bend the rules to make a deal, even if it's through third parties. Russia's entire economy is essentially built on evading trading rules now, and they have a whole new infrastructure in the BRICs network that didn't exist in 2016.