Sen. Barack Obama will walk straight into the lion’s den when he uses a campaign stop in Dayton, Ohio, this morning to pitch a plan to double federal funding for charter schools.

There’s perhaps no other state where the teachers’ union (part of Obama’s base) has so vehemently opposed these public schools, which operate free from many of the regulations that govern traditional public schools.

UPDATE: The Teacher Beat blog details a somewhat surprising reaction to Obama’s charter school proposal from the NEA. Meanwhile, the Democrats for Education Reform, which touts charter schools as a school reform tool, are cheering Obama on.

And Ohio’s charter schools have certainly given the Ohio Federation of Teachers and the Ohio Education Association ammunition, as leadership, management, and oversight of many of the state’s charter schools have been called into question. The state attorney general aggressively sued to shut down three in the Dayton area, where Obama was scheduled to deliver his speech this morning.

Although the Democrats’ official party platform embraces public charter schools (so long as they are “accountable”), Obama’s education plan makes no mention of these even though he’s said he generally supports them. Yet it’s clear from Education Week’s coverage of the Democratic Convention that some powerful forces within the party are pushing charter schools, even though they may not be popular with the teachers’ unions.

Details I’ve seen so far this morning are sketchy on his funding pledge, and who would benefit from the money. But Obama seems to be sending a message to voters—in a battleground state that he’d like to win in November—that he’s willing to stand toe-to-toe with the teachers’ unions and embrace something they’ve often worked against.

UPDATE: Obama also promoted merit pay, and EdWeek’s new Teacher Beat blog analyzes that.

UPDATE NO. 2: The Rev. Al Sharpton and New York City Schools Chancellor Joel I. Klein of the Education Equality Project have praised Obama’s speech, but they’re also interested in hearing the details.