The US Government's Support of Ukraine

The US government has been arming Ukraine to the teeth for years under Republican and Democrat administrations alike. Putin asked for a hard commitment that NATO would not admit Ukraine. We didn't give it to them. And then Putin invades. Why? This doesn't make sense. The US taxpayer dollars literally today are being used to pay the paychecks of the Ukrainian deep state. Nobody has given me a good answer on what national interest we're advancing by using hundreds of billions of dollars in our money to pay this random Eastern European nation. That's not some model of democracy. He's got his own issues of persecuting religious minorities in his own country.