McCain illness deprives U.S. Senate of crucial vote, Trump critic

U.S. Senator John McCain looks on during a news conference in Kabul, Afghanistan July 4, 2017. REUTERS/Mohammad Ismail

WASHINGTON (Reuters) - If John McCain's illness requires a long absence from the U.S. Senate, his colleagues will be deprived of a dealmaker and leading voice on national security, while America's allies will lose one of the few Republican critics of President Donald Trump's foreign policy.

The 80-year-old lawmaker and 2008 Republican presidential nominee, who was elected to a sixth Senate term last November, has been diagnosed with an aggressive form of brain cancer. He is vowing a quick return to the Senate.