Back before the conflagration that was World War II, some of Europe's great powers engaged in a surrogate struggle by arming the warring factions in the Spanish Civil War. It was a great way to test their latest weapons and tactics.
Here in our country and in our time, the role of Spain is being played by the state of Wisconsin, where a political civil war has raged for nearly 18 months presaging the fierce national politics of this presidential year.
Watch Wisconsin over the next four weeks, and you will see where we are headed as a nation in the months ahead.
On Tuesday, Wisconsin voters chose Tom Barrett, the mayor of Milwaukee, to oppose the sitting governor in a recall election on June 5. Barrett got over 50 percent in a four-way contest, setting up a rematch with Republican Scott Walker, to whom he lost in November 2010.
When Walker took office, he set in motion a more ambitious program than he had outlined in the campaign (or pursued in his years as Milwaukee county executive). The key element was a restructuring of the state's relationship to its employees, who lost not only many benefits but also the right to collective bargaining.
Thousands of state employees, including teachers, thronged the grounds of the State Capitol and occupied its hallways for weeks. State Senate Democrats decamped to Illinois for a time to deny the chamber a quorum. Recall elections got underway for legislators' seats and a (normally) routine re-election for a state Supreme Court justice became a donnybrook all its own.
(It was the judgeship battle of a year ago that prompted NPR Political Junkie Ken Rudin to initiate the comparison of Wisconsin to war-torn Spain in the late 1930s.)
After the preliminary rounds of recalls, a petition drive gathered more than 900,000 signatures to force a recall of Walker onto the ballot. So the state held its usual April primaries a month ago, added this week's primary to choose an anti-Walker champion and will vote again next month in the Barrett-Walker grudge match.
But no state has had more grudge matches of late than this one. It makes you wonder whether the state's politics will ever return to normal.
Barrett has chosen a return to normal as his campaign theme, blaming Walker and the hard right turn of 2011 for the subsequent upheavals. The appeal of that message may have helped him win this week's primary, for which he had only begun campaigning after winning a new term as mayor on April 3.
Milwaukee mayors are usually not a threat to be elected governor. Even within the Democratic Party, the big city candidate is often cast at odds with the rest of the state including the rival city of Madison, home to the State Capitol and the largest University of Wisconsin campus.
But in this particular intramural battle, the usual blue-collar and white- collar lines were blurred. The unions favored the Madison candidate, former Dane County Executive Kathleen Falk, over Barrett. They saw Falk as a truer friend who was there for them on the barricades of 2011.
Barrett, by contrast, had actually used a feature of Walker's anti-union law in his own negotiations with city employees in Milwaukee. Bitter as that pill was for some in the labor movement to swallow, it is hard to imagine they would not back Barrett now as the only option to Walker.
But will that be enough? With labor holding back in recent weeks, Barrett had yet to report even a million dollars raised. Walker, meanwhile, has amassed $25 million. Even with a sudden infusion, Barrett will be far less visible on TV in the weeks ahead.
It may not matter. The politics of pro-Walker and anti-Walker are so advanced in the Badger State now that relatively few voters remain persuadable. And the depth of that divide is expected to remain, regardless of the outcome on June 5.
The divides of our era seem to be deepening. Consider the big margin by which North Carolina adopted a constitutional amendment this week that denies legal standing to civil unions and domestic partnerships all in the name of banning gay marriages that were already outlawed in the state.
And consider the drubbing Indiana gave to six-term Senate icon Richard Lugar in Tuesday's Republican primary, which state treasurer Richard Mourdock won with 60 percent of the vote.
Lugar, a lifelong conservative, had two problems in the Tuesday test. He had been too much a mainstreamer in the Senate for the hardliners who dominate the Hoosier GOP base, and he had become too much a creature of the Capitol with attenuated ties back home.
Lugar's failure to maintain a home in his home state was overlooked in past cycles, as he regularly won re-nomination and re-election with ease. Now 80, however, he was no longer a legend so much as a symbol of all the Tea Party and other activists loathe about Washington. His friendship with a young Democratic senator from neighboring Illinois who became President Obama did not endear him to his party faithful.
And so Lugar will become available for service in the Cabinet, should he so choose, where he might be an ideal successor to Secretary of State Hillary Clinton no matter who's president in 2013.
Lugar then might end his career fighting the fires of war around the world, much as he has done as a senior leader on the Foreign Relations Committee. That would be fitting, yet sad, as he would be available for the job because he could not dampen the political fires at home.