WASHINGTON (CNN)  -- One of the the country's most powerful unions stepped up its campaign for a hotly disputed labor bill Monday, holding a rally on the eve of the bill's formal introduction in Congress. Workers rally in support of the Employee Free Choice act in Lafayette Square in Washington on Monday. The legislation -- the Employee Free Choice Act -- would create an alternate process for bringing a union into a workplace. It is supported by President Barack Obama and the Democratic congressional leadership, but is fiercely opposed by most congressional Republicans and corporate leaders, who fear it will saddle a sagging business community with new burdens at the worst possible time.
@highlight
One of largest unions holds rally in support of Employee Free Choice Act
@highlight
Bill would let employees openly sign a card demanding a union
@highlight
If a majority sign, company would have 90 days to negotiate
@highlight
Home Depot CEO, critic of bill says "this is how a civilization disappears"
Democrats and @placeholder may disagree sharply over the merits of the legislation, but leaders on both sides of the aisle freely admit it has the potential to significantly reshape the balance of power between business and labor for the first time in years.