Known as La Maestra or 'The Teacher', Gordillo headed the National Union of Education Workers or SNTE, which is estimated to have 1.5 million members.
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It is a significant voting bloc in Mexico and with Gordillo's backing - it helped to swing a close presidential election in Felipe Calderon's favor in 2006.
Gordillo's arrest is a political move and has to do with a settlement of accounts more than with accountability
Mexico: Taking down 'The Teacher' - Inside Story Americas - Al Jazeera English