Yet if Putin seeks a conflict with NATO, as those concerned by the escalatory nature of donating planes to Ukraine warn, he can easily create a casus belli on the basis of any policies that the United States and its allies adopted over the past couple weeks.

He has not done so, despite lambasting “hostile moves” by Western powers. Much like in his younger years as a low-level street thug in Saint Petersburg, Putin is being “street tough” by preying on the weak while staying away from stronger opponents.

If this account of Putin’s thinking is correct, it is equivocation and half-heartedness that are provocative — not displays of decisive, credible action. It follows that we are in a position to do far more than just provide Ukraine with old fighter jets. We should be helping to recruit foreign volunteer pilots and ground crews; beefing up the country’s supply of drones; intensifying cyberattacks targeting Russia and Belarus; and training volunteer fighters, particularly among expatriated Ukrainians.