Johnson decided on a campaign to use a discharge petition to force it onto the House floor.[126] Facing a growing threat that they would be bypassed, the House rules committee approved the bill and moved it to the floor of the full House, which passed it shortly thereafter by a vote of 290–110.[127] In the Senate, since the tax bill had passed three days earlier, the anti-civil rights senators were left with the filibuster as their only remaining tool. Overcoming the filibuster required the support of over twenty Republicans, who were growing less supportive because their party was about to nominate for president a candidate who opposed the bill.[128] According to Caro, Johnson ultimately could convince Republican leader Everett Dirksen to support the bill that amassed the necessary Republican votes to overcome the filibuster in March 1964; after 75 hours of debate, the bill passed the Senate by a vote of 71–29.[129][130] Johnson signed the fortified Civil Rights Act of 1964 into law on July 2.