The rebellion of the people took some lives, but failed to prevent enforcement of the law.

Meanwhile, some abolitionists openly sought to prevent enforcement of the law.

"It is for this reason that Freenet, a system designed to protect freedom of speech, must prevent enforcement of copyright," the project says.

Northeast is seeking an injunction against the city, to prevent enforcement of its recent ban on horizontal hydraulic fracking.

"Employers feel very strongly about maintaining access to immigrant workers, and exert political pressure to prevent enforcement from being effective," Professor Hanson said.

Corruption was a very powerful force preventing effective enforcement.

Interposition is considered to be less extreme than nullification because it does not involve a state's unilateral decision to prevent enforcement of federal law.

States sometimes have taken various actions short of nullification in an effort to prevent enforcement of federal law.

While it has been more effective, dangerous conditions persist and administrative difficulties prevent full enforcement.

We all agree that the present tachograph-based system has deficiencies which prevent effective enforcement of Community legislation currently in existence on professional drivers' hours.