How to reopen a closed proposal, really?

Question

We get quite a few questions requesting that Area 51 proposals be reopened. Essentially all of these turn into discussions of the merits of specific proposals that have recently been closed rather than the general procedure for reopening a proposal. Generally, someone will come and explain why the proposal was closed and why it deserves to remain closed forevermore. Even the frequent duplicate target How do I Re-open a Closed Proposal? is actually a discussion on the merits - all of the answers address why the specific proposal in question (Selenium Stack Exchange) shouldn't be reopened rather than explaining what the procedure is or should be for evaluating a request to reopen a proposal.

So, what is the actual procedure for reopening a proposal? I am speaking about a hypothetical (I don't have one in mind right now) proposal that is clearly meritorious - any issues with scope or clarity have now been resolved, the proposal now has the backing of a sufficiently large and devoted community, any users who might have engaged in vote fraud have been thrown in the dungeon, etc. The only barrier preventing us from moving forward is that our target proposal is currently closed. What must we do to get it reopened?

• Is there a specific reputation level we have to reach to be allowed to vote to reopen proposals?
• Should we flag the proposal for moderator attention with a custom flag requesting reopening and and explanation of why the proposal merits it (e.g. "I've edited the definition to be a lot more clear on what kinds of Widget questions are in-scope, I've told Dave the Vote Fraud Guy that he's not welcome anymore, and I've recruited the entire West Lake High School Widgets Club (500 members) and they are ready to make this proposal soar. Please reopen thx.")?

I do recognize that someone can simply start a new proposal, but that would cause the previous work (example questions along with all of the votes that have already been cast) to be lost.

Just to be clear, I don't have any specific proposal in mind that I would like to propose for reopening. I'm asking about the general case of how clearly meritorious proposals that just happen to have gotten closed get reopened. Reopening for questions has long been an integral part of the network - questions get closed, the asker comes back and adds details, then the question goes through the reopening process. A question getting closed doesn't have to be an end, but can be the beginning of becoming something greater. It's odd that the opposite seems to be the case for proposals - that a closed proposal is considered unsalvageable and good only for deletion.

Cases where a proposal is being evaluated for reopening could involve any of the following scenarios:

• A proposal is closed due to being poorly-defined, but the proposer edits the proposal to clarify its scope (e.g. changing "Writing Stuff from Babylon and Crap" to "Classical Babylonian Language and Literature").
• A proposal is closed due to failure to specify a community, but the proposer comes back and edits the proposal to indicate the community (e.g. "Sorry for not posting it, I thought the community field was optional. Our community is the faculty, staff, and student body of the Department of Classical Middle-Eastern Studies at the University of Ruritania West Campus. We are about 300-400 in total.").
• A proposal is closed due to just barely missing a deadline, but the proposer demonstrates that the proposal is nonetheless meritorious and that it is unlikely to miss a future deadline (e.g. "Sorry we missed the deadline, but we only missed it by two questions. I've recruited ten new participants from the East Campus and the Extended Studies department and we are ready to make up the missed progress and more if you give us 72 more hours. Thanks!").
• A new proposer has a community to back a proposal idea, but they know that an essentially identical proposal was made years ago by a different proposer and/or with a different community backing. They would like to "adopt" the old proposal, and make it (and the existing effort already put into it such as sample questions and votes) their own instead of starting all over from the beginning.

Answer 1

In this day and age, the answer is mostly: you don't.

We only reopen proposals if it was closed as a mistake or fundamental misunderstanding of the proposal. Those cases usually spawn a discussion post on Area 51 quickly to address that misunderstanding (I know of at least one that I have reopened because it was misunderstood).

But at the same time, very, very few proposals get closed for that reason. Most get closed because we would just never create a site for that topic, the proposer did not provide an appropriate existing community, or for automatic reasons. We would not reopen a proposal that was closed for any of those reasons.