Filibuster isn't in the constitution, it's just a Senate rule. Those can be changed with a simple majority vote. So f the filibuster.
You know who filibusters? People who know they would lose an up-or-down vote.
If you would lose an up-or-down vote, you deserve to see your ideas defeated. That's the point of voting.
I say this without respect to whoever is in power. Filibuster denies a vote that whiny tools know they would lose.
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Why should they have to? If you lose (whichever party you are), try harder next time. Elections have consequences.