WASHINGTON – The massive teachers’ strike in Chicago offers a high-profile test for the nation’s teachers unions, which have seen their political influence threatened as a growing reform movement seeks to improve ailing public schools.

The reforms include expanding charter schools, getting private companies involved with failing schools and linking teacher evaluations to student test scores.

Union leaders are taking a major stand on teacher evaluations, one of the key issues in the Chicago dispute. If they lose there, it could have ripple effects around the country.