The common core shift towards consistency and equality (internationally) is explained best in the short video Three-Minute Video Explaining the Common Core State Standards which can be accessed through the link: 

I am a visual learner, the artist and narrator do simplify the shift to the common core, however at times simplicity is the key to understanding very complex issues.  Note the importance of having shared standards across states without being forced to share curriculum.  The standards give us shared goals, our educators can provide the paths that lead towards reaching them.