People used to complain that the two parties are Tweedledee and Tweedledum. But this year nobody can say the election doesn’t offer stark alternatives. The problem is keeping track of who’s offering which alternative, as the candidates continually flip-flop.

Take education, for example. Suppose I told you Candidate A has supported rigorous academic standards, has stood up to the teachers’ unions — even been booed by them at their convention — and proclaimed the free-market principles that schools should compete for students and better teachers should get higher salaries. On the other hand, Candidate B says that competition hurts schools, that kids should be taught a radical left-wing civics curriculum, that we should throw more money at teachers’ unions — excuse me, at schools — and that rigorous academic standards should be replaced with the unions’ old lower-the-bar favorite, “portfolio assessment.”

Candidate A is Barack Obama. So is Candidate B.

Meanwhile, Candidate C has made an alliance with the teachers’ unions, opposed school choice, thrown money at the unions — excuse me, at schools — and even helped undermine a badly needed reform of bloated union pensions. On the other hand, Candidate D has broken with the teachers’ unions, demanded that schools should have to compete for students, and endorsed the most radical federal education reform agenda ever proposed by a national candidate, including a national school choice program for all disabled students.

Candidate C is Sarah Palin. So is Candidate D.

Obama has embraced education-reform principles never before seen at this level in the Democratic party. He not only supports charter schools, he justifies his support by arguing that competition arising from parental choice improves schools. In the last presidential debate, he said: “I doubled the number of charter schools in Illinois despite some reservations from teachers’ unions. I think it’s important to foster competition inside the public schools.” Even most Republican charter school supporters don’t appeal so directly to free-market principles.

This seems to have slipped by largely unnoticed even by the world of education wonks, but it’s a big deal. And it will be a big deal even if Obama is just saying what he needs to say to get elected and never again lifts a finger for the cause of education reform.

For decades, the unions have argued that the whole idea of bringing competition to education is crazy right-wing ideology. Now we can respond by asking if Barack Obama is a crazy, right-wing ideologue.

That’s not going to end the debate over competition in education. But it’s going to help.

Obama also supports reform on the crucial issue of differential pay. In every profession except education, your pay depends on what kind of assignment you take on and how well you perform. One of the main dysfunctions in the current system is that teachers are paid on a factory-worker scale where they don’t make more for working in tougher school assignments (guaranteeing that teachers flee those schools) or for performing better (guaranteeing that the profession will not attract top performers). When Obama mentioned his support for differential pay while accepting the endorsement of the National Education Association, the union actually booed him.