Recalls and impeachments are a remedy of last resort. Most of the time, voters who don’t like an incumbent choose to live with the offending politician until the next election, on the sensible theory that fixed terms of office and regular elections are adequate checks on abuses of power and extreme policies.

The question facing Wisconsin’s citizens is whether Republican Gov. Scott Walker engaged in such extraordinary behavior that setting aside his election is both justified and necessary.

Voters don’t have to get to this large question. Walker’s opponents forced next Tuesday’s recall vote by using the state’s laws in an entirely legitimate way. They gathered far more petition signatures than they needed, signaling that discontent in the state was widespread.

The result has been a fairly conventional campaign in which Walker once again confronts his 2010 opponent, Milwaukee Mayor Tom Barrett (D). At this point, preferring Barrett, an affable, moderate liberal, to the conservative firebrand Walker is reason enough to vote the incumbent out, but the broader case for recall is important.

Walker is being challenged not because he pursued conservative policies but because Wisconsin has become the most glaring example of a new and genuinely alarming approach to politics on the right. It seeks to use incumbency to alter the rules and tilt the legal and electoral playing field decisively toward the interests of those in power.

The most obvious way of gaming the system is to keep your opponents from voting in the next election. Rigging the electorate is a surefire way of holding on to office. That is exactly what has happened in state after state — Wisconsin is one of them — where GOP legislatures passed new laws on voter identification and registration. They are plainly aimed at making it much more difficult for poorer, younger and minority voters to get or stay on the voter rolls and to cast ballots when Election Day comes.

Rationalized by claims of extensive voter fraud that are invented out of whole cloth, these measures are discriminatory in their effect and partisan in their purpose. On their own, they are sufficient cause for the electorate to rise up and cry, “Stop!”

But Walker and his allies did more than this in Wisconsin. They also sought to undermine one of the Democratic Party’s main sources of organization. They sharply curtailed collective bargaining by most public employee unions and made it harder for these organizations to maintain themselves over time, notably by requiring an almost endless series of union elections.

The attack on unions was carried out in the name of saving state and local government money. But there is a big difference between, on the one hand, bargaining hard with the unions and demanding more reasonable pension agreements, and, on the other, trying to undercut the labor movement altogether. In the wake of the recession, mayors and governors of both parties have had to demand a lot from their unions. For Democrats, this often involved unions that helped elect them to office.

That is one of the reasons the party is well-represented in the recall by Barrett: He has been a tough negotiator in Milwaukee, to the consternation of some of its public employees. In the Democratic primary, unions spent heavily on behalf of Barrett’s main opponent, former Dane County executive Kathleen Falk. Although labor is now fully behind Barrett, Walker simply cannot cast his opponent as a captive of the movement. No wonder the Republican is closing his campaign with a demagogic ad on crime in Milwaukee. Walker knows he can’t win the last swing votes he needs on the basis of his record and his stand on collective bargaining.

The paradox of Wisconsin is that, although recalling a governor would be unusual, Barrett is the candidate of regular order, of consensual politics, Wisconsin-style. Wisconsin has had successful conservative governors before, Republican Tommy Thompson prominent among them. They enacted conservative policies without turning the state upside down. They sought to win over their opponents rather than to inhibit their capacity to oppose.

Walker seems to enjoy a slight advantage in the polls, having vastly outspent his foes up to now. Barrett, however, should have enough money to level the competition in the final days. This recall should not have had to happen. But its root cause was not the orneriness of Walker’s opponents but a polarizing brand of conservative politics that most Americans, including many conservatives, have good reason to reject.

ejdionne@washpost.com