Jared Kushner, a real estate developer married to Ivanka Trump, helped engineer his father-in-law’s successful run for the White House. This week brought news that President-elect Donald Trump is seeking a top-secret clearance for Kushner, likely to remain a close adviser, so he can attend security briefings.

The prospect of a security clearance brought a wave of protest. Critics said granting Kushner or any of Trump’s children access to classified information while they’re running the Trump empire would represent a conflict of interest. It would give them inside information they could use to make money.

In the House Oversight Committee, Democrats led by Representative Elijah Cummings tweeted their concerns about the possibility of Kushner getting access to government secrets.

.@RepCummings: #Kushner is not & never has been a gov employee & he has never been vetted by any agency to obtain access to classified info — House OversightDems (@OversightDems) November 16, 2016

Representative Bennie Thompson, another Democrat, put out a statement saying, “Our nation’s top secrets should not be carelessly or casually shared with those without a national security need-to-know.”

Neither congressman has a security clearance, nor does Trump. “Security clearances are not mandated for the president, vice president, members of Congress, Supreme Court justices, or other constitutional officers,” the Congressional Research Service recently reported, citing constitutional criteria.

The president-elect began receiving classified intelligence briefings on Tuesday. He has made it clear he wants Kushner present at those briefings, along with retired Gen. Michael Flynn, who has been offered the job of national security adviser.

So what’s involved in getting a security clearance? Do Trump’s close family members even qualify?

"As president-elect, he does get to bring whom he wishes to the transition table," Christopher Burgess, CEO of the security firm Prevendra, wrote for the website clearancejobs.com.

Burgess also pointed out that this has been done before: “John F. Kennedy’s transition team included his brother, Robert Kennedy," who eventually went on to become the president’s attorney general in 1961.

With that out of the way, here’s how clearances are granted—and to whom.

Secure jobs, not people

Security clearances are given out by a number of U.S. government agencies, including the departments of Defense, Energy, Homeland Security, Justice, State, and the CIA.

But it is important to note that clearances aren't given to people; they are attached to jobs.

At the State Department, human resources officials determine whether a “position requires a security clearance based on the duties and responsibilities of the position,” its website says. “If the position requires access to classified information, the position will be given an appropriate security classification."

Clearance parameters are less straightforward when it comes to presidential transition teams. If the president-elect wants an individual to participate in his security briefings, Burgess says the government would use the “need to know” formula.

It could “make a case, saying that if this person is here, they need a security clearance," he said.

So, if the president-elect wants his kids to give him advice, then they have a "need to know."

Burgess puts it this way: "In order to provide suitable counsel to the president-elect ... Trump’s transition team will need access"—even if that access is to top-secret material.

And they need it right away. Trump is already getting briefings, and the Jan. 20 inauguration is roughly 60 days away. But it normally takes between 90 and 120 days to process a single application for clearance.

However, there are a few ways Trump camp can get up and running quickly.

A fast track to clearance

First, the government can grant someone "interim clearance." Think of it as an "innocent until proven guilty" approach. Every candidate has to submit a standard form, called an SF-86, which lists every job they’ve ever had, every place they've lived, every country they've visited, and a host of other minutiae, including contact information for neighbors and close friends.

While the government investigates everything on the SF-86 (see one here), Burgess says an "interim clearance" gets them in the door, "so when they show up [they] can operate."

Another option is asking attendees at meetings where classified information is discussed to sign confidentiality agreements. Burgess, who held a clearance that expired after nearly 40 years, has since attended few meetings with administration bigwigs where top-secret stuff was on the table.

In that case, "before they opened their mouth[s], I signed a paper that I was about to hear classified info," Burgess said. That agreement also "laid out the penalties if I broke the rules" and talked outside of the meeting. Just for the record, penalties for violating such an agreement range from losing clearance to spending life in prison.

Can someone be denied clearance?

Yes, you can get knocked out of the running for things like illegal drug use, loyalty to other governments and, in some cases, a history of bankruptcy. Burgess says even that isn't automatically disqualifying if the candidate has returned to solvency. It's all about lifestyle choices that could make a candidate vulnerable to blackmail.

Differing levels of U.S. security clearances

So are there different kinds of clearances?

According to the federal job-search website Go Government, "Everyone hired for a federal job undergoes a basic background check of his or her criminal and credit histories to ensure that all federal employees are 'reliable, trustworthy, of good conduct and character, and loyal to the United States.'”

That applies to the more than 2 million people now working for the federal government.

But some people seek federal positions that might expose them to potentially sensitive national security information, so they need additional clearance. There are four basic kinds: confidential, secret, top secret and sensitive compartmented information.

So what's the difference among those four? It's pretty simple.

Confidential clearance "provides access to information or material that may cause damage to national security if disclosed without authorization."

Secret clearance "provides access to information or material that may cause serious damage to national security if disclosed without authorization."

Top secret clearance "provides access to information or material that may cause exceptionally grave damage to national security if disclosed without authorization."

Finally, sensitive compartmented information "provides access to all intelligence information and material that require special controls for restricted handling within compartmented channels."

The relatively few people with such clearance have access to really dangerous spy information, such as intelligence sources and methods.