Why does the Congressional leadership sometimes pull a failing bill from consideration and sometimes allow it to fail, even over and over?

Question

I hear it often repeated (sorry, no source) that leadership only allows a bill to be voted upon after they know they have the votes to pass it. Otherwise it would be a waste of time. Frequently, when a consequential bill is being considered, there is a lot of reporting on ensuring that a bill has the votes. I remember this process taking a considerable amount of time when the Democrats tried to pass the ACA. Presumably that is why Speaker Ryan pulled the AHCA from consideration without a vote a few months ago, they couldn't line up the votes.

Yet, in the last few weeks the Senate has now held several votes on replacing or repealing the ACA where, at least to the public it appeared they did not have much chance of passing, and indeed they did fail. Moreover, after the first bill failed, they tried voting on a few slightly different bills to see if they worked, and they didn't!

Why does leadership sometimes work to ensure passage before a vote is held and sometimes just vote and vote again?

Answer 1

Yet, in the last few weeks the Senate has now held several votes on replacing or repealing the ACA where, at least to the public it appeared they did not have much chance of passing, and indeed they did fail.

The Senate has held four main votes related to repeal, all this week (July 25th to 28th). Eleven votes total.

1. The motion to proceed, which succeeded. Required to proceed.
2. Repeal and replace, which failed. So that moderates could vote for it and conservatives against. So people don't ask why they didn't try this solution.
3. Clean repeal, which failed. So that conservatives could vote for it and moderates against. So people don't ask why they didn't try this solution.
4. Skinny repeal, which failed. But this is the one they though could succeed with the same support as the motion to proceed. Failed by one vote.

Why force other Senators to vote on a bill? It makes it easier to run challengers against them later. In particular, they now have most Democrats voting against

1. Additional premium support for the poor.
2. Single payer (not voting for; most Democrats voted Present rather than No).
3. Ending the Cadillac tax on high cost insurance.

Oddly enough, they did not force a vote on ending the individual mandate.