Iowa Gov. Terry Branstad is no stranger to politics – in fact, after six terms, he’s the longest-serving governor in U.S. history. But his next role as ambassador to China could prove to be the challenge of a lifetime, according to former Utah Gov. Jon Huntsman, who served in that role from 2009 to 2011.

“He will have to draw on everything he’s learned in his professional career, everything he’s experienced as a governor and apply those skills to something that is completely unique and different in his life,” Huntsman recently told the Des Moines Register. “It’s the most interesting job in modern-day diplomacy because the stakes are so high.

Brandstad was appointed in December 2016 but may not receive a Senate confirmation until April 2017. China referenced Branstad as an “old friend” upon hearing news of his ambassador appointment, possibly a callback to when Branstad told Chinese President Xi Jinping he was a “long-time friend” during a visit to Iowa in 2012.

"We welcome him to play a greater role in advancing the development of China-U.S. relations," China foreign ministry spokesman Lu Kang says.

The stakes are high, especially with the sometimes contentious atmosphere that has brewed around President Trump’s so-called “Twitter diplomacy.” China even called out Trump for his behavior in January, calling his Twitter obsession “undesirable.”

But China remains one of the largest U.S. trade partners. According to the Office of the United States Trade Representative, total trade of goods and services between the two countries totaled $659.4 billion in 2015, including $20 billion in U.S. exports of agricultural products to China.

That, coupled with various other geopolitical entanglements, will make Branstad one of the world’s most important diplomats, Harry Krejsa told the Des Moines Register.

“As the U.S. ambassador, you are the front line of American power and influence of the world,” says Krejsa, a research associate at the bipartisan Center for a New American Security think tank. “You are the face of American kindness and the warning of American strength. I can only imagine the sense of responsibility that comes with that, but also the privilege of having that level of service.”

The U.S. has sent diplomatic representatives to China since 1844, with the first ambassador, Nelson T. Johnson, appointed in 1929.