The 2014 election was “a major political defeat for the unions, particularly state-wide public sector unions, because it shows how much the voting public sees unions as part of the problem of persistent unemployment and underemployment, rather than being part of the solution,” Gary Chaison, a professor of industrial relations at Clark University, replied in response to my email. Chaison’s assessment:

The election of Republicans is indicative of the degree to which the voters have turned on the unions. There was once a time, two decades ago, when candidates to the governor’s officer sought the endorsement of major unions in his or her state; now they run on being anti-union crusaders. Quite a reversal of fortunes. The public sector was, for fifty years, the engine of union growth in America. This will happen no more. The brake on union decline is gone. The victory of Republican governors shows how much unions have lost their political power – now they are vulnerable to attempts to strip them of their power at the state level. Every new governor seems to be a Chris Christie, ready for a fight.

By 2013, 11.3 percent of wage and salary workers were covered by unions, down from 23.4 percent in 1983.

Republicans have good reason to target public sector unions. Without them, the share of the work force represented by unions would be even smaller than it is now. By last year, union coverage of private sector workers had fallen to 7.5 percent, from a high of roughly 35 percent in the mid-1950s. Government workers today make up 15.8 percent of the total work force, but union representation of this sliver has grown from less than 10 percent in the 1950s to 35.3 percent.

Norquist told the C.P.A.C. conference that conservatives hadn’t taken on public employee unions in the mistaken belief that “you can’t do anything about the public sector. The rules are set, and they elect the guys who set the rules.” But Walker’s success in winning a recall election, and in getting re-elected, has permanently changed thinking on the right, Norquist declared. By this reasoning, Walker’s survival and ultimate triumph demonstrates that changing the rules to make it more difficult to organize public workers, to collect dues and to bargain over wages and fringe benefits is politically viable, even in a Northern state.

In 2011, when Walker first took office, 37 percent of the nation’s 21-plus million public sector employees were union members; by 2012, this dropped to 35.9 percent; and last year, it fell to 35.3 percent.

If Republicans and conservatives place a top priority on eviscerating labor unions, what is the Democratic Party doing to protect this core constituency? Not much.

In fact, the Obama administration has undermined the bargaining leverage of the most successful unions by imposing a 40 percent excise tax, which takes effect in 2018, on health insurance premiums in excess of $10,200 annually for individuals, and $27,500 for families, in order to finance Obamacare. The provision, which covers what many of labor’s enemies call “Cadillac plans,” has provoked an angry response from labor leaders. They see the tax as threatening the continued survival of key health insurance benefits that unions have won as part of total employee compensation packages.

In an email to me, Joel Parker, national vice president of the merged Transportation Communications International Union and International Association of Machinists, wrote about the consequences of the new excise tax:

The result is a nightmare for union workers at large companies, and even worse for non-union workers. For the latter, companies will simply unilaterally cut benefits and/or shift to high-deductible plans. Institutionally, the bill weakens unions, one of the remaining core groups in the Democratic coalition. Private sector unions’ main selling point to non-union workers was superior health and pension plans. The health insurance advantage, if the excise tax is allowed to survive, will gradually disappear.

Democrats neglect the union movement at their peril. Not only does organized labor provide millions of dollars – the Center for Responsive Politics reports that unions spent $116.5 million on politics in 2013-14 – but union members are a loyal Democratic constituency. On Nov. 4, the 17 percent of voters who come from union households supported Democratic House candidates by a margin of 22 points, 60-38, while the remaining 83 percent from non-union households supported Republicans 54-44.