This statement only encourages aggression. We don't need to use nukes but saying we won't removes the fear anyone might have had of us using them. Right now would be the best time for Russia to hit us with everything they have.
The NGO Federation of American Scientists, in a prepared its report "From confrontation to a minimum deterrent", argues that current U.S. nuclear capability without the need for exaggerated to such an extent that constitutes a danger to America itself in the case, for example, natural disasters. In addition, more than 5,2 thousand warheads on alert and storage, absorb enormous resources in their care. The report proposes to reduce the number of nuclear warheads to the minimum of a few hundred units. But the transition to aim strategic missiles from densely populated cities in the Russian major economic objects of the Russian Federation.
According to the report, in the case of preventive destruction of these objects the Russian economy would be paralyzed, and the Russian will not automatically be able to wage war. The authors of the report with all its "humanism" could not hide the fact that in this case would inevitably perish at least one million Russian.
How much can destroy Russian?