Tim Kaine actually said...

The growing Russian asymmetric threat below the level of military conflict continues to target the United States, our allies, and partners.

Because we have failed to impose sufficient costs for this assault, not only has Russia not been deterred, it has been emboldened.

Why would any nation engage with us in serious dialogue to resolve differences if they fear we will later withdraw unilaterally?

If not for this agreement, Iran would likely be a nuclear power today.