The 2012 U.S. elections could be the most exciting and consequential in years. In Wisconsin, we might be looking at political Armageddon.

Wisconsin is a swing state in the presidential race. There is a wide-open contest for the U.S. Senate seat held by retiring Democrat Herb Kohl.

And Republican Gov. Scott Walker, along with his lieutenant governor and several Republican members of the state Senate, will probably face a recall election in late spring.

The furious drive to oust Walker is the sequel to last year’s dramatic battle over his plan to limit collective bargaining by public-sector unions. Walker won that fight, despite tumultuous pro-union demonstrations in and around the state capitol and a boycott of votes on the bill by the Democratic minority in the legislature.

For public-sector unions, the Walker recall is no mere exercise in payback. The unions, upon which Democrats depend heavily for funding and foot soldiers, say Walker must be ousted and his reforms reversed for the sake of the middle class. Progressive values — even democracy itself — are in mortal danger.

Actually, the opposite is true. The threat to such progressive goals as majority rule, transparent government, a vibrant public sector and equality comes from public-sector unionism.

I had supposed that Walker’s victory in 2010, along with the victory of Republicans in both houses of the state legislature, entitled the people’s choices to make policy until the next election.

I had not realized that Wisconsin’s voters were allowed to elect representatives to do everything except change the rules on collective bargaining.

“But Walker never campaigned on curtailing union rights!” his opponents cry. What rule of American democracy says that public officials may do only what they explicitly promised before taking office, and nothing else? By that logic, President Obama could be impeached because he opposed an individual mandate to buy health insurance during the campaign, then supported it in office.

Of course, collective bargaining in the public sector is inherently contrary to majority rule. It transfers basic public-policy decisions — namely, the pay and working conditions that taxpayers will offer those who work for them — out of the public square and behind closed doors. Progressive Wisconsin has a robust “open meetings” law covering a wide range of government gatherings except — you guessed it — collective bargaining with municipal or state employees. So much for transparency.

Even worse, to the extent that unions bankroll the campaigns of the officials with whom they will be negotiating — and they often do — they sit on both sides of the table.

Progressives believe, correctly, that government can and should provide such public goods and services as education, parks, or aid for the poor and disabled. It’s axiomatic that the public is entitled to the highest quality at the best possible price. Yet unions, by their nature, increase the price of public services, without necessarily increasing quality. Just ask New York Mayor Michael Bloomberg about the “rubber room” where, until a couple of years ago, hundreds of union teachers languished, on full pay, while awaiting disciplinary hearings.

Which brings us to equality. To be sure, public-sector pay and perks hardly put union workers in the 1 percent. But their clout enables them to enjoy retirement and health-care benefits that are often better than those available to the middle-class citizens whose tax dollars support them. What’s fair about that? Even after Walker’s bill, Wisconsin public employees pay just 5.8 percent of their salary toward their pensions and a modest 12.6 percent of their health-care premiums.

Last year’s battle left Wisconsin’s electorate deeply polarized. Recent polls show residents evenly split on recall. But the recall election is not a simple up-or-down vote on Walker; he’ll face a Democratic challenger. In the only poll to pit him against named opponents, Walker beat each one.

Maybe there are enough voters in Wisconsin who support actual progressive governance — as opposed to “progressive” interest groups — to retain Walker.

Or maybe it’s dawning on Wisconsinites — even some who don’t like Walker’s policies — that it would be a disaster to cut his term in half at the behest of a special interest group. That would confirm Wisconsin’s public-sector unions as the state’s de facto rulers, which really would be the end of democracy.