If you thought the climax of the Hollywood epic 'The Mueller Probe' was behind us and the credits were already rolling, think again.

The main characters are still plotting, and the drama has some way to run.

Democrats and Republicans are gearing up for a major legal battle over the report's redacted bits and underlying evidence.

One side says the whole matter is "case closed". The other says it is a "constitutional crisis".

No points for guessing which is which.

The fight is only widening the already massive chasm between them. And it may only be resolved with a presidential election.

Trump invoked executive privilege for the first time

His Attorney-General was already in a stoush with Congress for ignoring a subpoena to hand over the un-redacted report and related evidence, and then President Donald Trump invoked executive privilege over the whole kit and caboodle.

Attorney-General Bill Barr has also refused to testify privately before the House Judiciary Committee. And the President asked his former White House Counsel, Don McGahn, to refuse as well.

Loading

Mr McGahn features prominently in the Obstruction of Justice section of the report.

You remember — the one who refused to fire the special counsel under Mr Trump's orders, thereby saving the president from an act that would be hard to label as anything other than obstruction.

This is the first time Mr Trump has flexed his executive privilege. His Press Secretary, Sarah Sanders, and the Justice Department called the move "protective".

Loading

That was apparently based on the view that materials in the report are sensitive and in some cases classified, and cannot be legally released.

But if Democrats were curious about the report before, they're now really, really, really curious.

Democrats also say that "protective" executive privilege raises curious questions about the balance of power between the branches of government.

This is exactly the kind of document that Congress should have access to, the Democrats say, because it's a fundamental duty of Congress to provide oversight of the actions of the executive branch.

To be clear: US presidents use executive privilege now and again. But it usually shields certain conversations between the president and his advisors. The idea is that the chief should be able to solicit and receive candid advice.

It is rare for a president to use executive privilege in such a sweeping way.

House Democrats voted to hold Barr in contempt

US Attorney-General William Barr refused to attend the Mueller report hearing. ( AP: Andrew Harnik )

So, Democrats responded with their own plot twist.

The House Judiciary Committee voted along party lines to hold Mr Barr in contempt of congress.

The Democrats painted the move in apocalyptic terms, asserting that the very soul of the constitution is at stake.

Loading

The contempt resolution now goes to a vote in the Democrat-held House of Representatives, and is almost certain to pass with a simple majority.

It wouldn't be the first time this decade that Congress has passed a contempt resolution.

In 2012, for example, the Republican-held house voted to hold then-President Barack Obama's Attorney-General, Eric Holder, in contempt for refusing to turn over documents related to an illegal gun-selling scandal.

The lengthy legal battle in that case did not end until this week, when the administration finally released some documents and both sides decided to drop the dispute.

Technically, there are a few things that could happen in Mr Barr's case

1. Congress could detain Mr Barr.

Thanks to an obscure doctrine, the House could send its security force to arrest and detain him until he agrees to comply. The Capitol doesn't have a jail cell, though. And this doctrine has not been invoked since 1934. So, basically, this option is not going to happen.

2. Congress could refer the case to the US Attorney's Office for criminal charges.

For most witnesses, the Attorney's Office would seek an indictment for criminal charges. But since the witness is William Barr, and Mr Barr is technically the boss of all US attorneys it seems pretty unlikely that the office would press criminal charges against its boss. Right?

3. Congress could pursue a civil contempt citation.

They could sue the Attorney-General. This is unlikely to happen for similar reasons as above.

4. Congress could begin impeachment proceedings.

Not to be confused with actual impeachment, starting impeachment proceedings could tease out more of the evidence the Democrats are looking for.

House Speaker Nancy Pelosi has so far cautioned against that route, urging Democrats that it would be a political liability heading into a critical election period.

She said the President was goading the Democrats into impeaching him.

"Every single day, he's just like taunting, taunting, taunting because he knows that it would be very divisive in the country, but he doesn't really care. He just wants to solidify his base."

But other Democrats are keeping it on the table, and Ms Pelosi hasn't ruled it out as a last resort.

"He's becoming self-impeachable in terms of some of the things he's doing," Ms Pelosi said at an event this week.

"Every single day, whether it's obstruction, obstruction, obstruction, obstruction of having people come to the table with facts or ignoring subpoenas. Every single day, the president is making a case."

5. Congress could wait and do nothing.

President Trump has taken significant symbolic action. The Democrats have responded in kind.

Both sides could easily trumpet their smarts, blame the other side and let voters decide who's being the difficult party.

Yeah right.

Donald Trump Jr got subpoenaed — by a Republican

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 1 minute 28 seconds 1 m 28 s Donald Trump 'very surprised' by son's subpoena (Photo: Reuters)

And, in a fascinating sidebar, the head of the Senate Intelligence Committee subpoenaed Donald Trump Jr to testify over his Russia contacts.

The head of the Senate Intelligence Committee is a Republican (Richard Burr) so that complicates the party's "case closed" and "witch hunt" rhetoric.

Loading

It's worth noting that Mr Burr has already announced he is not running for re-election.

Mr Trump declared himself "very surprised" that his son was subpoenaed.

No doubt there are a few more surprising plot twists ahead.