Not only do you disagree with the current US position, but also the rest of NATO.
It was the Clinton administration that rightly started and supported the expansion of NATO. To not have done so would have allowed a potentially aggressive Russia to reimpose its control over Eastern Europe. Europe's security has been increased by NATO expansion. It would have defied "elementary strategic logic" to not have taken the opportunity to expand both the EU and NATO into Eastern Europe while Russia was weaker in the 1990s in order to prepare for the possible direction that Russia has unfortunately appeared to have taken today.
The United States would never compromise European security simply for the sake of having Russian cooperation on Iran and North Korea. Russia's ability to seriously impact both issues is limited, especially when compared to China on North Korea.
NATO has not moved any combat units into any of the Eastern European countries that now have NATO membership. The idea that NATO is a threat to Russia is simply absurd as any review of military force totals for NATO and Russia will show.
In addition, the small number of NATO countries that objected to starting the process of admitting Geogia and Ukraine this year did so not because of any need for Russian strategic cooperation on North Korea and Iran, but because they disputed that Georgia and Ukraine had met the requirements for NATO membership at this time. But no NATO country is actually against the future membership of Georgia and Ukraine in NATO at some point in the future.