By MATTHEW LEE
AP Diplomatic Writer
WASHINGTON (AP) — Secretary of State Antony Blinken will confront a number of daunting global challenges as he embarks this week on an around-the-world diplomatic tour that will test the Biden administration’s resolve on various fronts. From Russia and Ukraine to China and Myanmar, Blinken will have a full agenda as he travels first to Britain and then on to Southeast Asia for what will be his longest overseas trip yet as America’s top diplomat. At each stop, Blinken will be seeking support for U.S. efforts to tamp down tensions between Russia and Ukraine, push back on Chinese assertiveness in the Indo-Pacific and secure backing for pressure on Myanmar’s military rulers.