Mance v. Whitaker
18-663 interstate handgun sales. Waiting for a response 1/22/19. is that in process of trying to get cert or already has cert and the court is responding in some way?
Good question. The court is waiting for the government (Whitake, through the office of the Solicitor General) to file a response arguing why the petition should not be granted.
The 'normal' series of events during the petition stage (as opposed to the merits stage) would be that someone petitions the court for a writ of certiorari review, the respondent has the opportunity to respond, and then the petitioner has the ability to file a reply to the respondent's brief. Along the way, other groups and individuals have the opportunity to file amicus briefs in support of the petitioner. I don't think you can file an amicus opposing a grant of certiorari. If you can, it's very unusual.
This whole round of filings is entirely focused on whether the court should grant the petition. The petition is then distributed for conference where the justices decide whether or not they're going to grant cert. Sometimes those petitions get relisted which usually means they haven't made up their minds, are waiting for more information, or they've decided to deny cert and one or more justices needs time to write a dissent from cert opinion.
There are a lot of other things that can happen along the way. The defending party can waive their right to file a response. That happens a lot because most of these petitions are BS. Sometimes the justices will 'request' a response from the respondent. Sometimes they'll issue a CVSG or "Call for the Views of the Solicitor General". They did this recently and in a very unusual move gave the Solicitor General a deadline.
If the justices do grant cert, there's another round of filings and perhaps amicus briefs on the merits that leads up to a hearing months later and decision by the end of the term.
Sometimes the court will GVR - Grant Vacate and Remand - a petition and issue an unsigned
per curiam decision as they did in
Caetano without a briefing on the merits or a hearing.
Caetano is a great example where Massachusetts declined to file a response, but the court requested one anyway. The timeline on that docket is worth reviewing if you want to see how these things work.