Ireland has a national curriculum and all schools get equal financial support. Switzerland's cantons set their own curricula, but everyone takes the same test at the end of high school. All schools get equal financial support.
It's easier to reach consensus on a national curriculum, including which specific books are to be taught, in a relatively homogeneous country of about 5 million such as Ireland than in a sprawling, diverse country of 300+ million such as the U.S. Imagine if all the countries in the European Union had to come up with a continent-wide curriculum.
There are substantial differences in academic achievement across states. People bemoan the U.S. PISA results, but Massachusetts PISA results are among the world's best. If you made the students in Mississippi pass the same test (the MCAS) as students in Massachusetts do to get a high school diploma, the number of high school drop-outs produced would be unacceptably high. Common Core is an effort to fix the problem of differing state standards, but NCLB allowed states to set their own standards to avoid high failure rates in lower-performing states.
