Investing.com - Republicans have unveiled plans to slash the corporate tax rate to 20% as part of a sweeping tax overhaul, as they seek to secure a first major legislative victory for President Donald Trump.The tax bill calls for up to $6 trillion in tax cuts over the next decade for corporations, small businesses and individuals.Republican leaders on Thursday began the difficult task of selling it to their members before unveiling the proposed legislation in full ahead of a vote in the House of Representatives next week.Republicans have struggled to find ways to pay for tax cuts and limit a resulting increase in the deficit to $1.5 trillion — a threshold below which they can pass a bill with no Democratic votes.The White House is pinning hopes on tax reform as the best chance for retaining Republican control of Congress next year.A lack of consensus among Republicans has prevented them from delivering major legislation sought by Trump, as seen with the collapse of efforts to repeal Obamacare.If the bill passes the House it will head to the Senate where Republicans hold a slimmer majority.Meanwhile, democrats have criticized the proposed tax cuts as a giveaway to corporations and the wealthy that would harm workers and middle-class Americans.