Until last week there was one iron-clad rule when teaching government to US teenagers. If you mentioned "electoral college" they would roll their eyes, fall asleep or try to sneak out of the classroom.

But while Vice-President Al Gore and Governor George Bush suffer sleepless nights over Florida's crucial 25 electoral votes, high-school teachers across America are rejoicing. For once the complicated fine print of the constitution is catching teenagers' attention.

"I actually have students who go home and watch the news each night to get the latest updates," said Michael Barry, a political science instructor at Loyola Academy, a Jesuit secondary school in suburban Chicago. "It's the first and last thing they want to talk about each day. I'm still finding it hard to believe."

As the election count drags on, once uninterested students are transfixed by what Mr Barry calls "a truly teachable moment". Suddenly the dawn of the 21st century looks much like the 1870s and 1880s, an era no American remembers too well.

At Miami's Palmetto Senior High School, it used to be torture for Beth Bagwell to get her US history class to memorise tedious political rules that only applied to long-whiskered, long-forgotten leaders with names like Rutherford B. Hayes. (For those who don't know, he ran up against the electoral college back in 1876.)

"They always complained when they had to memorise this stuff - it had nothing to do with real life. It would never happen. They always skipped those questions on the tests," Ms Bagwell said of her class of 15 and 16-year-olds. "But now the teachers have the last laugh.

"And after this election they can never tell me that their vote doesn't count," she said. With 300 votes now between Mr Gore and Mr Bush, "this time it meant everything".

Phyllis McKown said her US history class at Costa Mesa High School in Los Angeles has been engaged in a heated, week-long debate over whether to keep the electoral college system.

"Most of them favour keeping the tradition alive, even though it can lead to weird situations like this," she said. "But never in my wildest dreams did I think the constitution would stir up this much passion."

The Clinton administration has done more than any other to bring history books to life. During the first presidential impeachment trial in 131 years last year, students watched on TV as the US Senate was turned into a massive courtroom with the Chief Justice of the Supreme Court presiding. It was a pageant no living American had ever seen before. Despite the tawdry scandal, you have to admit it was educational.

And now that President Clinton's contentious term is drawing to a close, his Vice-President is staging an intriguing history lesson of his own. For the first time since 1888 Mr Gore may win the popular vote while losing the electoral vote.

In fact, the only arcane procedure that has not been tested in the last two years is the one where the House of Representatives decides by ballot who will become the next president if no candidate obtains a majority of electoral votes.

That was the system that elected Thomas Jefferson in 1800 after 13 attempts, and it was last used 174 years ago. Due to the modern absence of third parties, though, it probably won't be revived this year.

"But with the way things are going," Ms Bagwell said, "there's always 2004."