Surveying the fall in support for the governments of Barack Obama, New York City's progressive Mayor Bill de Blasio and France's Socialist President François Hollande, a diagnosis of the current crisis begins to emerge: The political left can win elections but it's unable to govern.

Once in office, the left stumbles from fiasco to fiasco. ObamaCare, enacted without a single vote from the opposition party, is an impossible labyrinth of endless complexity. Bill de Blasio's war on charter schools degenerated into an unseemly attack on poor New York minority children. François Hollande's first act in 2012, like a character in a medieval fable, was to order that more tax revenue be squeezed from the French turnips.

Surveying the fall in support for the governments of Barack Obama, New York City's progressive Mayor Bill de Blasio and France's Socialist President François Hollande, a diagnosis of the current crisis begins to emerge: The political left can win elections but it's unable to govern.

Once in office, the left stumbles from fiasco to fiasco. ObamaCare, enacted without a single vote from the opposition party, is an impossible labyrinth of endless complexity. Bill de Blasio's war on charter schools degenerated into an unseemly attack on poor New York minority children. François Hollande's first act in 2012, like a character in a medieval fable, was to order that more tax revenue be squeezed from the French turnips.

Mr. Obama's approval rating is about 43%, Mr. de Blasio's has sunk to 45% after just two months in office, and Mr. Hollande hit the lowest approvals ever recorded in the modern French presidency. The left inevitably says their leaders failed them. The failure looks self-inflicted.

Three European academics asked themselves recently how 19 United Nations summit meetings have been unable to produce a treaty on global warming. Why the cause of climate change has fallen apart is described in "Melting Summits," a paper and cautionary tale just published in the Academy of Management Journal by Elke Schüssler of Germany, Charles Clemens Rüling of France and Bettina Wittneben of the U.K.

No idea in our time has had deeper political support. Al Gore and John Kerryhave described disbelievers in global warming as basically idiots—"shoddy scientists" in Mr. Kerry's words. But somehow, an idea with which "no serious scientist disagrees" has gone nowhere as policy. The collapse of the U.N.'s 2009 Copenhagen climate summit was a meltdown for the ages.

In an interview with the Academy of Management about her paper, Bettina Wittneben of Oxford University, who supports a climate-change treaty and has attended 13 climate meetings, summarized the wheel-spinning: "Sometimes I just find myself shaking my head after talking to participants in recent COPs [the U.N.'s climate meetings]. They'll come back from the meetings simply brimming with enthusiasm about the networking they've done, the contacts they've made, the new ideas about their research they had or the new angles to lobbying they thought of. But ask what progress was made in terms of global policy initiatives, and all you get is a shrug."

Put differently, it's not about doing something serious about global warming. It's really all about them (a virus threatening American conservatism as well). The "them" at the U.N. summits included not just the participating nations but a galaxy of well-financed nongovernmental organizations, or NGOs.

They travel under their own acronyms. The environmentalists are ENGOs, the trade unions are TUNGOS, indigenous peoples are IPOs, business and industry are BINGOs and women, gender and youth groups are YOUNGOs.

These are the left's famous change agents. The authors dryly describe what they actually do as "field maintenance." Instead of being "catalysts for change," they write that "more and more actors find COP participation useful for their purposes, but their activity is increasingly disconnected from the issue of mitigating climate change."

And little wonder. The failed efforts to get the global-warming treaty done reflect the issue's departure from anything practical. It's impossible to read this history of global warming's demise without hearing resonances of ObamaCare's problems.

The text of the climate-change treaty at Copenhagen in 2009 included "thousands of 'brackets,' or alternative wordings." A participant described the puzzle palace: "There are more and more parallel processes, and everything must be negotiated at the same time. The number of . . . negotiation issues has increased and many of these issues . . . are discussed in different places at the same time. . . . Very few people understand the whole thing." Maybe they could just pass it to find out what's in it.

One organization specialist calls this phenomenon "social deadlock." ObamaCare is social deadlock. But the American left keeps doing it. This isn't the 1930s, and smart people on the left might come to grips with the fact that the one-grand-scheme-fits-all compulsion is out of sync with the individualization that technology lets people design into their lives today.

Rather than resolve the complexities of public policy in the world we inhabit, the left's default is to simply acquire power, then cram down what they want to do with one-party votes or by fiat, figuring they can muddle through the wreckage later. Thus the ObamaCare mandates. Thus candidate de Blasio's determination, cheered on by the city's left-wing establishment, to jam all its kids through an antique public-school system. The ObamaCare mandates are a mess, and the war on charter schools is an embarrassment.

Making the unworkable work by executive decree or court-ordered obedience is one way to rule, and maybe they like it that way. But it isn't governing.

Write to henninger@wsj.com