WASHINGTON, Jan 18 (Reuters) - Democrats will push for a "talking filibuster," requiring U.S. senators to physically take the floor and speak nonstop, likely for hours, to halt legislation, if Republicans block voting rights bills, Senate Majority Leader Chuck Schumer said on Tuesday. President Joe Biden is trying to secure a federal law to counter an onslaught of state limits to poll access before Republicans, who are opposed to the change, possibly capture one or both houses of Congress in the mid-term elections in November.