(CNN)As if their stalled and tattered agenda wasn't proof enough, Democrats just got a poignant reminder of the precarious nature of life in a 50-50 Senate, especially ahead of an impending Supreme Court nomination.

After news broke Tuesday that New Mexico Sen. Ben Ray Luján suffered a stroke last week, there was palpable concern for a valued fellow senator and then relief among his colleagues that he was expected to make a full recovery.

At 49, Luján is one of the geriatric Senate's young bucks, yet his sudden hospitalization, at least for now, deprives Majority Leader Chuck Schumer of a functioning majority if he needs to call a short-notice vote.

(And this muddies any Supreme Court nomination.)