Former Florida Governor Jeb Bush, a possible Republican candidate in the 2016 presidential election, expressed his discontent on Sunday over the fact that President Barack Obama had held a meeting with Cuban leader Raul Castro.

In a post on Twitter, Bush wondered why Obama had met with Castro while snubbing Prime Minister Binyamin Netanyahu when he recently visited Washington.

“Obama meets with Castro but refused to meet w/ @netanyahu. Why legitimize a cruel dictator of a repressive regime?” wrote Bush.

The two leaders held an historic formal meeting on Saturday on the sidelines of the a Panama City convention center.

Obama and Castro met for about an hour, with Obama telling reporters before the meeting, according to Fox News, that it was time to try something new and to engage with both Cuba’s government and its people.

“What we have both concluded is that we can disagree with a spirit of respect and civility,” Obama said. “And over time, it is possible for us to turn the page and develop a new relationship between our two countries.”

He thanked Castro “for the spirit of openness and courtesy that he has shown during our interactions” and pledged to do whatever he could to “make sure that the people of Cuba are able to prosper and live in freedom and security.”

Castro, for his part, said he agreed with everything Obama had said. However, he added the caveat that they had “agreed to disagree” at times.

The meeting between Obama and Castro was the first time an American and Cuban leader have met since 1958. It came on the heels of an announcement on December 17 that the two countries would renew diplomatic ties after more than 50 years of hostility.

The move to normalize ties with Cuba came after Havana released Jewish-American contractor Alan Gross in exchange for three Cubans held in the United States for spying.

Obama previously angered Republicans when he  shook the hand of Castro at the memorial ceremony in Johannesburg for late South African leader Nelson Mandela.