Tim Kaine actually said...

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.

Withdrawing from it could accelerate Iran's path to nuclear weapons and make America less safe.