President-elect Donald Trump wants Congress to investigate an NBC News report. (Evan Vucci/AP)

President-elect Donald Trump is upset that NBC News on Thursday previewed the substance of an intelligence briefing he was set to receive on Friday, and now he wants Congress to investigate.

The information leaked to NBC wasn't exactly earth-shattering. Top intelligence officials on Thursday testified at a congressional hearing — in public, in other words — that they believe Russia attempted to meddle in the U.S. presidential election. Citing two unnamed intelligence officials, NBC filled in some additional details contained in a classified report that already had been delivered to President Obama — the one Trump was slated to receive on Friday.

“The report on Russian hacking also details Russian cyberattacks not just against the Democratic National Committee but the White House, the Joint Chiefs of Staff, the State Department and American corporations,” NBC reported.

The Washington Post on Thursday reported another detail contained in the report: U.S. intelligence agencies intercepted celebratory communications among Russian officials in the wake of Trump's victory. Trump did not complain about The Post's report, specifically.

These are interesting tidbits, but they hardly qualify as state secrets. It seems likely that they were always going to come out, anyway, in an unclassified version of the report on Russia, which intelligence agencies plan to release after meeting with Trump.

While Trump's pride might have been wounded by the thought that journalists received information before he did, the incoming president probably will have a hard time getting members of Congress too worked up about these leaks. Trump clearly resents the dissemination of info that could be viewed as delegitimizing his win in the slightest, but even Republicans appear uncomfortable with his effort to undermine intelligence agencies' conclusions about Russian interference.

In short, the investigation Trump requested on Twitter is unlikely to materialize. Even if it did, NBC News almost certainly would be protected by the First Amendment, so long as its journalists did not commit a criminal act to obtain the information it published. The landmark Pentagon Papers case of 1971 set a clear legal precedent: News outlets can publish information, even if the source of the information broke the law by leaking it.

However, the media cannot completely dismiss Trump's tweet because it could signal a plan to crack down on leaks in the next administration — even harder, perhaps, than in the last two. The Committee to Protect Journalists described Obama's attempts to keep information in-house in a 2013 report:

In the Obama administration's Washington, government officials are increasingly afraid to talk to the press. Those suspected of discussing with reporters anything that the government has classified as secret are subject to investigation, including lie-detector tests and scrutiny of their telephone and email records. An “Insider Threat Program” being implemented in every government department requires all federal employees to help prevent unauthorized disclosures of information by monitoring the behavior of their colleagues.

And of course, during George W. Bush's presidency a special prosecutor investigated the leaking of CIA operative Valerie Plame's name to the New York Times. Reporter Judith Miller spent almost three months in jail for contempt of court in 2005 because she refused to identify the government source who leaked the name. There wasn't — and still isn't — a federal shield law that empowers journalists to protect their confidential sources.

Miller's source, I. Lewis “Scooter” Libby, chief of staff to Vice President Dick Cheney, ultimately released her from their confidentiality agreement. Libby was convicted in 2007 on charges related to the leak.

The Miller case is an extreme example of what can happen when an administration makes it a priority to track down leakers. It is rare for a reporter to go to jail.

But Trump wouldn't necessarily have to put journalists behind bars to make their lives harder. If Friday's tweet foreshadows a witch-hunt culture in the Trump administration, it could be harder than ever for reporters to persuade government officials to talk.