The President had a decade-long bromance with his Russian counterpart and is thankfully changing tack, writes Michael McFaul.

On Monday, Trump said that Russia's failure to reach a negotiated settlement with Ukraine within 50 days would lead to his administration imposing a 100% tariff rate on Russian imports as well as what he called "secondary tariffs" on countries that have continued to do business with Moscow.

Russian President Vladimir Putin has sacrificed an estimated 1 million of his soldiers, killed and wounded, in a three-year campaign to crush Ukraine. Now President Donald Trump is betting that his go-to economic weapon — tariffs — can succeed where Ukrainian drones and rockets haven't,