His whirlwind foreign trip complete, President Donald Trump faces a slew of political and policy challenges at home and mushrooming inquiries into allegations that Russia meddled in the U.S. election and had improper dealings with his campaign and associates.

Mr. Trump returned to Washington late Saturday after a nine-day trip to the Middle East and Europe, his first trip abroad as president.

“Just returned from Europe,” Mr. Trump tweeted early Sunday. “Trip was a great success for America. Hard work but big results!”

Before heading home, he recounted what he called “home run” success of his first foreign trip, as he addressed American troops stationed at Naval Air Station Sigonella in Sicily, Italy.
Awaiting him at home were reports that his son-in-law and senior adviser, Jared Kushner, spoke with Russia’s ambassador to the United States about setting up secret communications with Moscow during the presidential transition.

White House aides prepared for potential changes ahead, with the president mulling a staff overhaul amid frustrations over what he views as his communication team’s failures to push back against allegations. A rally planned Thursday in Iowa was postponed due to “an unforeseen change” in Trump’s schedule.

While overseas, Mr. Trump’s longtime attorney, Marc Kasowitz, joined a still-forming legal team to help the president shoulder the intensifying investigations into Russian interference in the election and his associates’ potential involvement. More attorneys with deep experience in Washington investigations are expected to be added, along with crisis communication experts, to help the White House in the weeks ahead.