By Susan Cornwell and Steve Holland WASHINGTON (Reuters) – The battle to pass a COVID-19 relief bill demonstrated how hard things will be for U.S. President Joe Biden’s Democrats in Congress, facing opposition from right and left as they try to score big wins with small majorities. A smiling Senate Majority Leader Chuck Schumer sang the praises of Democratic unity on Saturday after his chamber approved the $1.9 trillion coronavirus aid plan, one of the largest economic stimulus packages ever. He predicted it will be approved by the House of Representatives next week and quickly signed into law…
