The states also pledged to hold colleges more accountable for ensuring students graduate.
Such changes would require time and significant legislative and political work, as teachers unions, school boards, legislatures, and parents would be affected. Governors, state school chiefs, and business executives will lead the efforts in each state.
''This is the biggest step states can take to restore the value of the high school diploma," said Governor Bob Taft of Ohio, a Republican who is cochairman of Achieve, which is coordinating the effort.
The other states are Arkansas, Georgia, Indiana, Kentucky, Louisiana, Michigan, New Jersey, Ohio, Oregon, Pennsylvania, Rhode Island, and Texas.
Their network will aim to enforce the American Diploma Project, an effort launched last year to prepare every high school student for college-level work.
It calls for big changes -- requiring every student to take rigorous math and English regardless of career plans, and tying college admissions to high school exit exams, as examples.
States will maintain the option to adopt what they want, but they have agreed to broad points, such as requiring students to take a test of their readiness for college or work.
The weekend session on high schools drew most of the nation's governors, in town for a four-day meeting that includes discussions with President Bush.
Education Secretary Margaret Spellings went before the governors to promote Bush's budget proposal and commend the state leaders for making high school achievement a national priority.
''Getting every child to graduate high school with a meaningful diploma in their hands is one of the biggest challenges our country faces," Spellings said yesterday. ''It's never been done. That's why there is push-back from both sides of the political spectrum. In Washington, like your state capitals, when both sides grumble, it means you're doing something right."
Bush, seeking to expand the No Child Left Behind law he championed, wants Congress to require two years of additional state testing in high schools.
