What is the significane of Johnson's convincing Ed Dirksen to vote for the Bill ?​

The new york times journalist Clay Risen contends in The Bill of the Century that Johnson’s contribution to the Civil Rights Act’s success was “largely symbolic.” One might say the same thing about Neil Armstrong’s walk on the moon. Sometimes symbolism is substance—especially where the presidency is concerned. The head of the executive branch firmly seized the initiative, taking up a moribund bill addressing the nation’s most agonizing problem. Here was Johnson, president for only five days, working out of the Executive Office Building because the White House was still occupied by Kennedy’s family and staff, with an election already looming less than a year away. Instead of proceeding tentatively, as most anyone in those circumstances would have done, he radiated decisiveness, betting everything he had right after he got it. As Caro shows so persuasively, from that moment, Johnson’s urgency and purpose infused every stage of the bill’s progress. And in the days and weeks that followed, the stagnant cloud that had settled over Kennedy’s agenda began to lift.

the answer to your question is

the treaty of hopewell