The budget that President Obama proposed on Thursday is nothing less than an attempt to end a three-decade era of economic policy dominated by the ideas of Ronald Reagan and his supporters.

The Obama budget — a bold, even radical departure from recent history, wrapped in bureaucratic formality and statistical tables — would sharply raise taxes on the rich, beyond where Bill Clinton had raised them. It would reduce taxes for everyone else, to a lower point than they were under either Mr. Clinton or George W. Bush. And it would lay the groundwork for sweeping changes in health care and education, among other areas.

More than anything else, the proposals seek to reverse the rapid increase in economic inequality over the last 30 years. They do so first by rewriting the tax code and, over the longer term, by trying to solve some big causes of the middle-class income slowdown, like high medical costs and slowing educational gains.

After Mr. Obama spent much of his first five weeks in office responding to the financial crisis, his budget effectively tried to reclaim momentum for the priorities on which he campaigned.