Enlargement is not making NATO weaker and more prone to risk.
In general, it almost amuses me that there are analysts who say that of course Russia wants buffer states in the west to put more distance between them and potential invaders. We should understand their desire. Yet none of them ever says that it is a good idea for NATO to want a buffer in the east.
And while there are analysts who say that NATO is stretching itself out by expansion; none of them say Russia's desire to expand a buffer zone west risks stretching out Russian defense capabilities.
With Macedonia on the path to joining NATO, no doubt their military is small. But they will join a NATO committed to the 2% defense spending goal. So they will get better.
And their territory will provide some depth to Bulgaria, Romania, and Greece from Russian threats from the Aegean and Black Seas. Further, by joining NATO Macedonia will not be able to allow a non-NATO state to have a base in their territory.
And rather than being persuasive, the author's historical examples of how a small state might entangle America in a war with Russia is farcically wrong. Neither the American participation in the European-instigated Libya War of 2011 nor the German involvement in the Austro-Hungarian crisis with Serbia had anything to do with America or Germany, respectively, responding to a military threat that committed the country to helping an ally.
As long as America refuses to embark on an offensive war under Responsibility to Protect doctrine because Macedonia lobbies for a war against Russia; and refuses to give Macedonia a "blank check" to challenge Russia over some dispute, we won't be dragged into a war out of nowhere.
Really, if Macedonia declares war on Russia, NATO is not obligated to defend Macedonia.
Indeed, the author's example of the risk of war when Russian troops entered Kosovo at the end of the 1999 NATO war against Serbia was only possible because Russian troops were sitting in neighboring Bosnia and they raced into Kosovo to make sure they had a seat at the table. Removing the ability of Russia to put troops into positions behind NATO's eastern front might be a good idea given that example, eh?
Remember, the alternative to NATO expansion was leaving states that rejected Soviet/Russian domination in a gray zone where they'd be vulnerable to Russia when it recovers from the nadir of the post-Soviet morale, military, and economic collapse. Georgia and Ukraine represent what can happen to those gray area states when Russia turns their gaze to those former imperial territories.
Does anybody think that Russia would leave those ex-territories free absent NATO membership?