Barry Posen, Ford International Professor of Political Science at MIT, explains in an article published here in the National Interest.
The two sides have not managed a bilateral nuclear crisis in a very long time, and one does not really wish to find out if they can easily recover their Cold War vintage crisis management skills.
Thus, even the preparation of a Russian battlefield use of nuclear weapons would likely produce at least some preparations for a strategic nuclear exchange. But the aftermath of nuclear attacks will be even worse. The United States will be grasping for tools with which to punish the Russians. It is unlikely that US military planners will be able to assure the president that this is the last Russian move. Instead, US military leaders may advise additional US nuclear preparations. Even if the United States is quite judicious in what those preparations might be, they will surely elicit additional moves from the Russians.
In sum, if the Russians even begin the preparations for a localized use of small numbers of “low yield” theater weapons, a process will be set in motion that brings both sides’ intelligence and military forces of all kinds, all along the Russian periphery, to much higher levels of activity and alert. Candidly, if I were the Russians, this alone would deter me. But there is no reason to believe that they will be so restrained. Strategic nuclear forces would themselves likely increase their readiness to some extent. The two sides have not managed a bilateral nuclear crisis in a very long time, and one does not really wish to find out if they can easily recover their Cold War vintage crisis management skills. To avoid such an experiment, the United States needs to carefully limit its military and political objectives, and the means it employs to achieve them.
Barry R Posen is Ford International Professor of Political Science at MIT and director emeritus of the MIT Security Studies Program