Roy Moore thinks he's been called to put God back where God belongs: in the classroom, in the bedroom and in the courtroom. Moore is a former chief justice of the Alabama supreme court, first elected in 1999. He holds that Jesus is good, taxes are bad, abortion is really bad and the state should use its power to punish homosexuality, which he called a "criminal lifestyle".

Moore was booted off the court in 2003, falling foul of the constitutional prohibition against government-endorsed religion. As chief justice, he'd parked a two-ton Ten Commandments stone monument in the doorway to the state judicial building and refused to move it.

Now, Moore's back, lamenting what he sees as our catastrophic moral decline, warning that secularism, gay marriage and the teaching of evolution will inevitably lead to sharia law – and trying to get reinstated. Since Alabama is both rock-hard Republican and churchier-than-thou, Moore has a real shot at getting elected again.

Win or lose, he is Exhibit A in a growing trend of politicisation of the American judiciary.

Allowing party hacks and legal toffs to appoint judges is a lousy idea. Allowing citizens to vote them into – or out of – office is an even lousier idea. Most Americans have only the haziest understanding of due process and can't even name their state supreme court justices. But throw party politics and a ton of money into judicial races, and they become as unsavoury as your average name-calling, scandal-mongering, shit-slinging congressional campaign.

If you believe that the judicial branch of government should be as apolitical as possible in this fallen world, having judges raise hundreds of thousands, sometimes millions, of dollars from people who may appear before them one day in order that they can run 30-second spots begging for votes, leaves a still worse taste.

The United States supreme court dumped a gallon of arsenic into the stew with its Citizens United decision, ruling that corporations and unions can give unlimited amounts of money to political campaigns. Retired US supreme court Justice Sandra Day O'Connor, who opposed Citizens United, says:

"If you're a litigant appearing before a judge, it makes sense to invest in that judge's campaign. No states can possibly benefit from having that much money injected into a political judicial campaign. The appearance of bias is high, and it destroys any credibility in the courts."

Nevertheless, across the country – in Montana, West Virginia, Illinois, Texas, Oregon – state judicial races attract fat checks from those who want to buy a court. In Iowa, Republicans are spending big to unseat Justice David Wiggins. In 2009, the Iowa supreme court ruled that same-sex marriage is legal in a unanimous vote. Conservatives had a fit of the vapours, then vowed revenge.

Two years ago, a failed gubernatorial candidate called Bob Vander Plaats helped unseat Chief Justice Marsha Ternus and Associate Justices Michael Streit and David Baker. Now, Vander Plaats is at it again, bringing reinforcements in Louisiana Governor Bobby Jindal and culture warrior former Senator Rick Santorum. They're touring Iowa on a bus, urging people to vote against Wiggins and, since the Iowa caucuses are the first step on the road to the White House, getting a jump on the 2016 campaign.

The Republicans' biggest target this year is the Florida supreme court – specifically, Justices Peggy Quince, R Fred Lewis and Barbara Pariente, who must win a majority of votes to keep their seats. Lewis and Pariente were appointed by Lawton Chiles, Florida's last Democratic governor; Quince, one of two African Americans on the seven-member court, was chosen jointly by Chiles and incoming Republican Governor Jeb Bush. She and Pariente are the court's only women.

For the first time ever, the Republican party of Florida (RPOF), aided by their Tea Party shock troops, is mounting a concerted campaign against specific justices. RPOF pretends this is some grassroots effort, an outburst of populist anger at a bunch of out-of-touch liberal judges. But the power (and the money) behind the effort comes from an outfit called Americans for Prosperity, funded by the Koch brothers.

The play here is to create three shiny new vacancies on Florida's highest court, which would be filled by Tea Party poster boy Governor Rick Scott. This is a rightwing wet dream: a forelock-tugging, corporation-loving, quiescent court, which would ignore inconveniences such as the Clean Water Act and the 14th Amendment, and never get in the way of the free market.

"Merit retention" of judges is supposed to be a mechanism for citizens to rid the courts of the incompetent and the unethical. No one accuses Quince, Lewis and Pariente of incompetence or unethical practices. The best Republicans can do is call them "judicial activists", a meaningless phrase they throw at any jurist who rules against them. The great Brown v Board of Education decision in 1954, the one which declared segregation unconstitutional – that's judicial activism. Handing the presidency to George W Bush on the dodgiest of legal theories in Bush v Gore is high-minded and statesman-like.

Republican disdain for Florida's court goes back to the 2000 presidential recount imbroglio, when the justices refused to allow certification of Florida's dubious election results. In the dozen years since, the court has been the only institution standing against attacks on unions, public education and public employees. The court has stopped Republican governors and the Republican-controlled legislature from trying to curtail women's reproductive rights and knock down that metaphorical, but necessary wall separating church and state. Most recently, the court slapped down Gov Scott's attempt to take power over all state agencies, and rejected Republicans' pet 2010 initiative that would have let Floridians refuse to buy health insurance no matter what federal law may say.

Republicans won't admit they're trying to saw off one of our government's three branches; they prefer to run television ads attacking Quince, Pariente and Lewis for their "extremism" and accusing them of being soft on crime. The latter charge refers to the court's 5-2 decision in 2003 granting Joe Elton Nixon, a confessed murderer, a new trial because his defense had been incompetent. Nixon was never going to be freed from prison and there was no question of his guilt. But that pesky old US constitution (the one conservatives swear they love, but seem not to have ever read) guarantees all citizens a fair trial – not just the nice people. Yet, to hear the Republicans squeal about it, you'd think that the Florida supreme court had declared Nixon innocent, popped open a bottle of champagne and given him a ride to the nearest Hooters.

All this happened nine years ago. Six years ago, when Pariente, Quince and Lewis were last up for retention, there was nary a peep out of the GOP. But that was before the Republican party lost what was left of its marbles and began muttering to itself about Kenyan socialists, black helicopters and UN invasion forces.

In the meantime, our liberties are threatened as the rule of law is weakened by grubby politics, and our justice system grows increasingly partisan.