WASHINGTON – The center of Washington was on lockdown Thursday as more than 20,000 armed National Guard troops were being mobilized due to security concerns ahead of the presidential inauguration of Joe Biden. Washington Police Chief Robert Contee said the US capital was facing “a major security threat”, one week after supporters of outgoing President Donald Trump stormed the US Capitol to try to block Biden’s confirmation as election winner. A day after Trump was impeached in Congress for alleg