There are plenty of rumors swirling about which Republican presidential candidates will receive protection from the Secret Service.

If you believe one set of headlines, Secret Service protection has already been “activated” for Donald Trump and Ben Carson. But according to a senior Obama administration official, Trump and Carson only just submitted their formal requests — Trump on Tuesday and Carson on Oct. 16. Now, the Department of Homeland Security (DHS) will begin the process of formally determining whether protection is merited.

So what does it take for a candidate to qualify for a Secret Service detail? The practice started in 1968, after the assassination of Robert Kennedy, and there’s a higher bar than you might think. After a written request to Homeland Security Secretary Jeh Johnson, campaigns must follow several guidelines in order to be considered, the senior administration official said.

First, they must establish that they are a serious candidate with at least some chance of becoming president. This can be achieved in a variety of ways. Candidates are asked to show they are actively campaigning, have entered in at least 10 state primaries and have received contributions totaling $10 million, according to a Secret Service FAQ document on the subject. Later in the campaign cycle, candidates for protection must demonstrate that they have obtained at least 10 percent of their party’s committed convention delegates.

Second, DHS conducts a threat assessment as a way to understand the potential dangers facing a candidate. Candidates cannot simply vouch for threats against them and expect to receive protection. Threats are considered in tandem with the other criteria.

The guidelines are new for this election — although they were implemented in 2008, they didn’t apply to candidates who started running in 2007. And another administration official said that while candidates are strongly encouraged to meet these criteria, Secret Service details could be awarded regardless of whether they check every box.

Secret Service officials have met with Trump and Carson campaign staff, at the campaigns’ request, to explain the process, the official said.

The next step in the process involves a special panel convened by Johnson to review whether the request comes from a “leading candidate” from a qualified party in the presidential race. The group conducting the review includes the speaker of the House, the House minority leader, the Senate majority leader, the Senate minority leader and one additional member selected by the Senate, according to the FAQ.

The final decision is made by Johnson, the DHS secretary. Does the request come from a “leading candidate”? Are there enough threats to warrant Secret Service protection? Are there other factors that weigh in favor of assigning a detail?

Only Johnson can say, in the end.

Carol D. Leonnig contributed to this story.