Putting Russia on the State Sponsor List Would Be Bad Policy
Ill-advised designations related to terrorism are often intended to be obstacles to future diplomacy.
Delaney Simon and Michael Wahid Hanna make a compelling case against designating Russia as a state sponsor of terrorism:
If designating Russia a state sponsor of terrorism were a purely symbolic act, as some proponents suggest, then there would be little or no cause for concern beyond worries about appearing ineffectual. But a designation would not be simply an expression of opprobrium: it would inject additional risk into a situation that is already tremendously perilous. The U.S. administration has been wise to resist efforts to push it in this direction. It should continue to do so.
Designating other governments as state sponsors of terrorism can sometimes be a way for our government to express its hostility towards the other state even when there is little or no evidence that it sponsors terrorist attacks or terrorist organizations. The Trump administration chose to put North Korea and Cuba back on the list of state sponsors as an excuse to pile on more sanctions on the former and to pander to voters that oppose the latter. Neither government was sponsoring terrorist groups or terrorist attacks when the designations were made and neither had been doing anything like that for decades, but both were put back on the list anyway because it pleased Trump to do it.