Why would filibuster work if opposition has more than enough votes to pass bill?

Question

If the Civil Rights Act of 1964 was passed in the Senate with an overwhelming vote of 73–27, then why would a filibuster even matter?

This is my reasoning, which I know is incorrect, hence the question: this particular legislation passed with 73 votes, 6 votes more than the 67 votes needed to close the debate/delay/filibuster and move on to the voting.

With 73/100 votes wanting to pass this legislation, why didn't 67 of these senators just stand up and order the filibuster to end? I assume the filibuster was done by senators in the 23 votes.

I'd understand how a delay would work if the votes were closer (ie. 55-45), but when almost 3/4 of the senate will vote for something, how can a small group challenge that by filibustering for 3 days?

Answer 1

The cloture only happened for the substitute Civil Rights bill; from Wikipedia:

After 54 days of filibuster, Senators Hubert Humphrey (D-MN), Mike Mansfield (D-MT), Everett Dirksen (R-IL), and Thomas Kuchel (R-CA), introduced a substitute bill that they hoped would attract enough Republican swing votes in addition to the core liberal Democrats behind the legislation to end the filibuster. The compromise bill was weaker than the House version in regard to government power to regulate the conduct of private business, but it was not so weak as to cause the House to reconsider the legislation.

On the morning of June 10, 1964, Senator Robert Byrd (D-W.Va.) completed a filibustering address that he had begun 14 hours and 13 minutes earlier opposing the legislation. Until then, the measure had occupied the Senate for 60 working days, including six Saturdays. A day earlier, Democratic Whip Hubert Humphrey of Minnesota, the bill's manager, concluded he had the 67 votes required at that time to end the debate and end the filibuster. With six wavering senators providing a four-vote victory margin, the final tally stood at 71 to 29. Never in history had the Senate been able to muster enough votes to cut off a filibuster on a civil rights bill. And only once in the 37 years since 1927 had it agreed to cloture for any measure.

On June 19, the substitute (compromise) bill passed the Senate by a vote of 73–27, and quickly passed through the House–Senate conference committee, which adopted the Senate version of the bill. The conference bill was passed by both houses of Congress, and was signed into law by President Johnson on July 2, 1964.

So the filibuster was not without effect (of weakening the final bill somewhat).

Answer 2

Different legislatures have different rules. And also specific legislatures have different rules for different activities.

Filibuster
Filibuster in the United States Senate

And indeed, they may change the rules over time.

Nuclear option

In some legislatures the rule for some kinds of debate is that as long as a speaker continues to speak, he or she cannot be stopped. There may be rules about breaks, what happens if the legislature wants to take a rest, if the speaker can temporarily give the floor to somebody else then get it back, etc. and etc. Or, the speaker may be required to stand while speaking until he/she gives up.

But, in some cases, as long as the person doing the filibuster continues, the rules say the debate can't be closed. And they don't even have to talk about the issue at hand. People have been known to read the phone book, sing, etc.

Five famous filibusters

So, if the speaker has more stamina than the legislature, or the public or press is on his/her side and shames the legislature, it is potentially possible for a single person to stop a legislature from taking a specific action.

It is by no means the only delaying tactic that has been used at times.

Minority rules

But every such tactic has the potential of working, or of backfiring. If other members of the legislature, or the public or the press, have a favorable opinion then it can work. If they have an unfavorable opinion, then the delaying persons can find they have lost all support. Most politicians in legislatures with meaningful debate will have at least some degree of concern for such support. And the same is true of methods used to close off the delays.