John McCain, a leading Republican senator who ran for U.S. president in 2008, died Saturday at age 81 surrounded by his family, his office said.Current Republican U.S. President Donald Trump, whom McCain had criticized for his America First policy and conciliatory stance on Russia, wrote on Twitter, "My deepest sympathies and respect go out to the family of Senator John McCain."McCain had been battling an aggressive form of brain cancer that was discovered in 2017, Reuters news agency said. He had not been seen at the U.S. Capitol in 2018, it said.McCain had lambasted Trump in a series of t…READ FULL ARTICLE