President Joe Biden has made it clear he’s running for a second term, arguing he’s the best bet the Democrats have to once again beat Donald Trump. His supporters have brushed off concerns over his low approval ratings and advanced age. As the incumbent president, Biden, 81, is an almost surefire lock to be handed the Democratic nomination next summer. Still, some Washington Democrats are seeking a choice — or a backup plan — just in case. They’re pushing to get Minnesota Congressman Dean Phillips on Washington’s Democratic presidential primary ballot on March 12. “The problem isn’t just that …