WASHINGTON - With more than 600,000 Americans dead of COVID-19 and questions still raging about the origin of the virus and the government's response, a push is underway on Capitol Hill and beyond for a full-blown investigation of the crisis by a national commission like the one that looked into 9/11.It is unclear whether such a probe will ever happen, though a privately sponsored team of public health experts is already laying the groundwork for one.Given that most of the disaster unfolded on President Donald Trump's watch, many worry that politics will get in the way of any inquiry, as happened when Republicans came out against a commission to investigate the Jan.