Special counsel Robert Mueller (L) arrives at the U.S. Capitol for closed meeting with members of the Senate Judiciary Committee June 21, 2017 in Washington, DC.

The federal investigation into Russian meddling in the 2016 election that has consumed the first two years of President Donald Trump's term in office will not be over soon.

For months, there has been speculation that Mueller was wrapping up his probe into any links between Trump and Russia. Ty Cobb, a former White House lawyer focused on the Mueller probe, said in August 2017 that he would be "embarrassed" if the probe continued into 2018.

But recent events have ensured that the inquiry will last well into 2019.

Legal developments in cases brought against two former Trump officials have proven that neither the president, who has blasted investigators for what he has called "an illegal Hoax that should be ended immediately," nor Mueller, who has provided no indication of when he may conclude, can overcome the slow marching bureaucracy of the U.S. federal court system.

The delays come as Trump and those in his orbit face parallel investigations from New York investigators, who are examining Trump's charitable foundation, and from Democrats in Congress, who will take over the House of Representatives in January and have vowed to closely examine Trump's personal finances and businesses.

One loose end that observers thought would be wrapped up before the new year was the sentencing of Trump's former national security advisor, Michael Flynn, who has pleaded guilty to lying to federal investigators. But on Tuesday, a federal judge in Washington threw a wrench in that plan.

During an explosive hearing, U.S. District Court Judge Emmet Sullivan postponed sentencing in the case pending further cooperation from Flynn with Mueller's prosecutors.

The judge did not provide a new sentencing date, but he ordered a status report in the case by March 13. The previous status report in the case was filed in mid-September, three months before Tuesday's sentencing hearing.

The postponed sentencing pushes Mueller's inquiry beyond the tentatively scheduled sentencing date for Trump's former campaign chairman Paul Manafort, who has pleaded guilty to a range of federal crimes in Washington, and was found guilty of eight other federal crimes in Virginia.

In the Washington case, which is scheduled to wrap up second, U.S. District Court Judge Amy Berman Jackson has tentatively set Manafort's sentencing date for March 5.

The continuation of the inquiry into Trump's third year in office threatens to further enrage the president, who ordered the firing of the special counsel in June 2017 and again considered shutting down the probe in December of that year, The New York Times has reported. In both cases, the president ultimately backed down. Trump has denied any collusion.

Mueller may also bring new charges. Allies of Roger Stone, a Trump confidante and conservative provocateur, have been brought to testify before Mueller's grand jury in recent weeks.

Stone, who has been scrutinized for his connections to Wikileaks, the anti-secrecy group that published hacked material during the 2016 election, has denied any wrongdoing and claims that he has not been contacted by Mueller's prosecutors.

But in August, the former Trump advisor said he expected to be indicted and established a legal defense fund. Stone also has predicted that Trump's son, Donald Trump Jr., will be indicted. Stone and Trump Jr. have denied any wrongdoing. Neither man has been charged with any crime.

Mueller, a notoriously tight-lipped former FBI director, has provided little notice to the public for any of the more than 100 criminal charges he has brought so far in connection with his inquiry, and there is no reason to believe he will be more forthcoming in future cases.

To date, the only public statement Mueller has issued came the day he was appointed 19 months ago.

"I accept this responsibility and will discharge it to the best of my ability," he said.

A spokesperson for the special counsel declined to comment.