US Defense Secretary Lloyd Austin has paid tribute to US President Joe Biden as an “extraordinary guardian” of the country’s security. He was “deeply grateful” for Biden’s leadership and statesmanship, Austin said in a statement after Biden announced he was withdrawing from the race to be the next president. “He has a secure place in American history as one of our great foreign-policy presidents,” Austin said. “President Biden has been a stalwart defender of free government, a fearless foe of tyranny, and a historic champion of an open world of rules, rights, and responsibilities.” The entire …