It's not so easy for Biden to evolve on Ukraine joining NATO

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President Joe Biden's support for Ukraine has evolved in key ways to give Ukraine ever more deadly firepower for its defense, but he remains opposed to fast-tracking what some allies say is the ultimate protection: inviting Ukraine into NATO.

That singular position, meant to avoid dragging the US into war with Russia, has remained even as others have slowly fallen.

Fighter jets. After opposing NATO members supplying Ukraine with F-16s, the US recently relented to international pressure from Europe, although it still will not supply Ukraine with its own.

Patriot missiles and modern tanks. The US changed course to provide access to the Patriot missile defense systems and modern Abrams tanks, speeding up the deployment process earlier this year.

Longer-range missile systems. After first refusing to supply longer-range missile systems, the US has pledged to provide ground-launched small diameter bombs, known as GLSDBs, that could give Ukraine's military the range to strike within Russia. The US could go even further if it decides to give Ukraine access to different, longer-range missile systems known as ATACMS, as other NATO allies like the United Kingdom have done with their Storm Shadow missile system.

Cluster munitions. Now Biden has made the "difficult decision" to give Ukraine cluster munitions. It's controversial since multiple other NATO members have promised never to use the devices and the decision drew condemnation from human rights groups.