By David Jackson, USA Today–

President Donald Trump opened an historic second summit with Kim Jong Un here Wednesday by pledging to push for North Korean denuclearization, even as he faced a political firestorm at home that threatens to eclipse any progress.

“I think we’ll be very successful,” Trump said as he and Kim posed for a ceremonial handshake at a classic old hotel in the capital of Vietnam.

“I will try very hard to work something out on Denuclearization & then making North Korea an Economic Powerhouse,” Trump had tweeted before the meeting, adding that he believes China, Russia, Japan and South Korea will help the effort.

But Trump’s diplomatic efforts come as his former personal attorney, Michael Cohen, is expected to allege “criminal conduct” by the president in his first public testimony later Wednesday before Congress.

Trump met with Kim for a brief private conversation to be followed by a 90-minute dinner, all marking their first face-to-face encounter since the two met in Singapore last summer.

The initial ceremonial events, which will splash across U.S. television screens early Wednesday morning, are expected give way to more substantive talks on the second and final day of the summit Thursday.

Trump is trying to get Kim to commit to specific steps to eliminate nuclear weapons programs, while Kim wants to Trump to lift economic sanctions that are crippling his impoverished nation.