Margaret Thatcher, Britain's greatest prime minister since Winston Churchill, will be laid to rest Wednesday. In life, Thatcher never rested. American politicians, who have fallen into a bad habit of legislating for the camera, need to learn her habit of sweating the details instead.

Thatcher believed that, in the end, you could only succeed by preparing and thinking. As she said, "First you win the argument, then you win the vote." Advertising only sticks if the product is worth advertising. Thatcher was driven by ideas. She once confronted her researchers by banging Friedrich Hayek's "The Constitution of Liberty" on the table and saying sternly, "This is what we believe."

American politicians used to prepare for high national office, too. For Harry Truman, the only thing new in the world was "the history you don't know." Thatcher agreed: To be a great leader, you need to know enough to make up your own mind. Before she visited the Soviet Union, the civil service tried to brief her. She demanded a seminar with the West's best historians of Russia instead.

Ronald Reagan also read a lot. But he didn't brag about it. He thought he'd get more done if people believed he was a slacker. His public persona was an act. So was Dwight Eisenhower's. For the cameras, Ike played golf and took it easy. Behind the scenes, he ran the show. He recognized that the important thing wasn't to look smart. It was to be wise.

Today, politicians read so their press offices can boast about it. President Barack Obama has carefully cultivated his reputation as a great reader. Like all recent presidents, he keeps us informed of what's on his reading list because he badly wants us to know that he's clever.

According to the Daily Beast, our president read exactly 24 books between 2008 and 2010, a selection carefully chosen for its balance and diversity. Two books on Lincoln the Republican, two books on FDR the Democrat, plus the great Caribbean poet Derek Walcott and some left-wing economics. This isn't reading: It's reputation management.

We legislate in the same uninformed way. Former House speaker Nancy Pelosi infamously said of Obamacare: "We have to pass the bill so you can find out what is in it." Thatcher would have hated Pelosi's quip more than Obamacare itself. If you support a law, you should be able to explain it.

Right now, liberal Washington's obsessions are gun control and immigration -- both backroom deals that everyone is supposed to rush to endorse. And it's not just liberals who are all flash: Mitt Romney's campaign showed what happens when conservatives try to avoid substance.

Too many of our laws today are not really laws. They're grants of authority to unelected bureaucrats to start making rules. So far, Obamacare has produced more than 2,000 pages of regulation. Dodd- Frank financial industry reform law has generated 9,000 pages, and it's not fully implemented.

This isn't law. It's a full employment act for lawyers. And it comes from the same bad habit: When a government tries to do too much, lawmakers end up delegating away the vital business of thinking through policy. All that's left is chasing the camera. It says a lot about Thatcher that she never liked watching replays of her past triumphs.

Our politicians aren't lazy. The constant quest to be in the public eye is exhausting. But working hard isn't the same as studying to be great. Thatcher has a legacy not just because she outworked her opponents. She outthought them, too. If America's leaders want to build an enduring legacy, they need to take a lesson from the Iron Lady and start doing their homework.