Sentence:  Compare this statement of a nineteenth-century judge with how Congressman Martin , according to the Daily Labor Report of Sept. 19 , 1961 , defends the necessity of enacting anti-trust legislation in the field of labor `` if we wish to <WSD>prevent</WSD> monopolistic fixing of wages , production or prices and if we wish to preserve the freedom of the employer and his employees to contract on wages , hours and conditions of employment '' . 
Meaning of the word marked with <WSD> tags:  keep from happening or arising; make impossible