BRUSSELS — In the recent horse-trading for the European Union’s top jobs, Josep Borrell Fontelles was among the more surprising of the choices, given his age and his tendency to say controversial things.

Mr. Borrell, a 72-year-old Spanish Socialist, suggested in a speech last year that all the United States had to do to achieve independence was to “kill four Indians.” He has spoken harshly of President Trump’s “hostility” toward Europe, “to describe us as foes.” When Mr. Trump suggested building a wall in the Sahara to keep out migrants, Mr. Borrell asked: “Does he know how big the Sahara is?”

Mr. Borrell, the Spanish foreign minister, is nonetheless likely to be approved in the coming weeks as the European Union’s next foreign policy chief, taking over from Federica Mogherini, the leader of the European External Action Service.

The switch, which requires the approval of the European Parliament, could not be happening at a more critical time. The foreign and security policy of the European Union is, generously put, a work in progress. As Ms. Mogherini prepares to leave her post, the challenges of a Trumpian America, a more aggressive Russia and a rising China have rendered Europe newly exposed.