This reasoning is so simple and at first glance so irrefutable that for a quarter of a century it has rendered excellent service to the modern labour movement as a logical weapon against the anarchist phantom and as a means of carrying out the idea of political struggle to the widest circles of the workers

Please fix the punctuation.
This reasoning is so simple and at first glance so irrefutable that, for a quarter of a century, it has rendered excellent service to the modern labour movement as a logical weapon against the anarchist phantom and as a means of carrying out the idea of political struggle to the widest circles of the workers.