By Andrew Chung

WASHINGTON, Feb 21 (Reuters) - The U.S. Supreme Court on Tuesday declined to revive a newspaper's challenge on free speech grounds to an Arkansas law requiring state government contractors to pledge not to boycott Israel, a policy the publication's lawyers called a threat to a constitutionally protected form of collective protest.

The justices turned away an appeal by the Arkansas Times, represented by the American Civil Liberties Union, of a lower court's ruling dismissing its lawsuit that claimed that the measure punishes participation in political boycotts based on the viewpoint expressed in violation of the U.S. Constitution's First Amendment guarantee of free speech.

The Arkansas law, passed in 2017, requires public contracts to include a certification that the contractor is not engaged in a "boycott" Israel, which includes "actions that are intended to limit commercial relations" with Israel or "Israeli-controlled territories." It applies to contracts worth at least $1,000. (Reporting by Andrew Chung; Editing by Will Dunham)