Don't let the threat of filibuster cause you to back down. Make the GOP actually do it, or shut up.
Why is this important?
The GOP has blocked a number of legislative initiatives by merely threatening filibuster. That has been enough to get the Democrats to back away from their own proposals, and has led to gridlock in Congress. Why should the threat of filibuster be enough? The fallout from televised coverage and news coverage will be so negative, it will lead to them backing down. Make the GOP actually do it, Jimmy Stewart style. They will have to put up or shut up.