US State Department spokesman Ned Price at a briefing on September 14 explained the reason that Biden administration doesn’t support declaring russia a state sponsor of terrorism.
“We believe that there are more targeted approaches that we could take that would hold the Russian economy and the Russian Government to account, to continue to impose those massive costs and consequences, without incurring those unintended consequences. We have heard from humanitarian organizations, we have heard from NGOs of their sincere and profound concerns that designating Russia as a state sponsor of terrorism would hinder their ability to deliver humanitarian assistance inside Ukraine, leaving aside what they could do inside Russia.”
“So to sum it up, there are steps that we have taken and there are steps that we are discussing with Congress that we could take that would have effects that are analogous to those envisioned by the SST without those unintended consequences.”