The president of the United States has one of the most powerful bully pulpits in the world.

President Trump has used that platform to spread his populist message through language often shorn of diplomatic niceties and demeaning of his opponents. And his language has been picked up by a number of leaders in other countries to offer justification of their own actions and to promote like-minded policies.

Some leaders — or leaders of national institutions — have used similar language to go after political opponents, push their own populist agendas or even shield themselves from criticism of human rights abuses or the erosion of democratic norms.

The latest example came on Friday, when the Nigerian army cited remarks by Mr. Trump to defend its owns actions after fatally shooting unarmed protesters.