NATO is a mess — and that’s nothing new:
NATO enlargement post-Cold War was essentially a push from the liberal internationalist lobby within the Clinton administration, led by Madeleine Albright and backed by the German leaders like Volker Rühe. Evidence suggests there was significant academic opposition to NATO expansion during that time, including from the father of the strategy of Cold War containment, George F Kennan. He said NATO expansion would end up being the greatest blunder of our times.
There still remains a significant academic as well as strategic opposition to further NATO expansion, as almost everyone in the strategic community foresaw that an inexorable push of frontiers towards a former superpower like Russia would not only invite an understandable military backlash but install a hardline regime with a siege mentality within a former adversary.
Also, the cost-benefit analysis of providing an American taxpayer-funded security umbrella to corrupt, violent smaller countries not only is a heavy and needless burden based on a flawed strategy but encourages those smaller countries to risk conflict assuming that American cavalry is just around the hills.
However, the current ongoing debate on NATO funding is not that. It is not new, either. One of the strongest speeches against NATO was from former Defense Secretary Robert Gates in 2011. He highlighted, almost prophetically, that if NATO leaders failed to immediately increase their funding and improve hardware, retention, and deployment capabilities, future American presidents would find it hard to justify to the electorate why they should pay for rich countries like Germany to have bloated social security programs, and not invest more in their submarine fleet or air force. Incidentally, Germany has only four serviceable Typhoons in the Luftwaffe and has refused to increase its NATO budget.
Ideally, after winning the Cold War, NATO should have thrown itself one hell of a victory party, then promptly disbanded. The former member states could have maintained close military relations in a strictly de facto entente cordiale, but a defensive alliance with no external enemy is a contradiction in terms. That contradiction, plus unwise expansion into Eastern Europe, have given us the worst possible outcome: Provoking Russia while encouraging allied free-ridership.