A watchdog group is questioning whether Democratic Sen. Barbara Boxer could have been more transparent over a year ago in voluntarily disclosing the extent of her past mortgages with the company Countrywide. But Boxer aides strongly argue that the watchdog group’s complaints are without merit and suggest the questions are suspiciously timed, considering how the California senator is locked in a tough re-election fight. Boxer, as chairwoman of the Senate Ethics Committee, led a yearlong investigation beginning in 2008 into whether two Democratic senators acted improperly by being part of a VIP Countrywide program that gave influential clients favorable treatment....