Russia is our greatest challenge? Russia was the only thing standing between ISIS and the rest of the world when Obungo was president and Hitlary was massaging Al Bagdaddy’s toes.
Vladimir Putin is not altogether immune to reason and negotiations, while the leaders of ISIS have no interest in either negotiating or listening to reason. One side or the other must die, is the way ISIS looks at things, and they intend to be so fierce that the other side just curls up, submits, and gets slaughtered anyway. Or they die trying.
We have no business being either allies or enemies of the Russian Federation. We may from time to time have common goals, and for those purposes, we can come to a (perhaps uneasy) truce with each other to defeat the common foe. But nothing lasting or irreversible could ever come of such a diplomatic or military conjoining.