As President Donald Trump heads overseas for his first international trip as President, many in the international community will be watching his national security adviser, Gen. H.R. McMaster, who has just experienced one of the most politically challenging weeks of his career.

The trip — to Saudi Arabia, Israel, the Vatican, a NATO summit in Brussels and a G7 summit in Sicily — will be fraught with international risks, and much of it is riding on the ability of McMaster to steer the President in the right directions.

“It can be difficult to advise the President effectively given his seemingly short attention span and propensity to be easily distracted,” a source knowledgeable about McMaster’s day-to-day challenges told CNN.