A week of two halves in US politics as Trump hits highs and lows

Nancy Pelosi stole the State of the Union show and Trump was acquitted of impeachment charges in a varied week for the US president

President Donald Trump holds up a newspaper during the 68th annual National Prayer Breakfast. AP

An extraordinary working week in US politics is coming to a close with President Donald Trump cleared of impeachment amid a flurry of viral moments from the opposition.

The head-turning events of the week started in the rural state of Iowa, which held its Democrat caucus vote – the first of election season – on Monday.

An attempt to step into modernity with a voting app ended in chaos and confusion, with no result after more than four days.

“Irregularities” and  “coding errors” have been blamed by the Iowa Democratic Party as reasons for the delay.

With 97 per cent of districts reporting, former mayor Pete Buttigieg is leading Senator Bernie Sanders by only 0.1 per cent (26.2 to 26.1).

It was a bad week for former vice president Joe Biden, earlier considered a front-runner to become Mr Trump's challenger. Mr Biden looks to be trailing in fourth place in Iowa's preliminary results.

As the Democratic vote arrives in New Hampshire on Tuesday, Mr Biden will need a good showing to stave off the momentum of Mr Buttigieg and Mr Sander.

Mr Sanders is going from strength to strength funded by small donations. In January he raised more than $25 million from nearly 650,000 people.

Even outsider Mike Bloomberg had a positive start to the caucus season.

The billionaire former New York mayor decided to skip the early voting states, instead doubling his advertisement spending in the large, delegate-rich “Super Tuesday” states that vote on March 3.

The Iowa chaos served as a comfortable distraction from Mr Bloomberg's low polling figures and he looks set to take the moderate mantra in the race against Bernie Sanders if Mr Biden continues to stumble.

Adding to the Iowa chaos, the head Democratic National Committee Tom Perez called for a "re-canvass" on Thursday. Some activists in the party had called on Mr Perez to resign.

Almost 1,300 kilometres from Iowa, a different kind of discord took over Washington, DC.

Mr Trump’s 78-minute State of the Union speech on Tuesday night was highly campaign driven and full of dramatic moments.

The US President refused to shake Speaker Nancy Pelosi’s hand at the start of the speech, but was upstaged by her at the end  as she tore up her copy of his address.

Ms Pelosi’s stunt as Mr Trump was receiving a final applause from the Republican side of the chamber captured the level of polarisation in US politics.

While many viewed the shredding as “disrespectful” and lacking class, it was effective in stealing the limelight from her rival by using his own divisive and base-driven tactics.

But Mr Trump recovered swiftly. On Wednesday he was cleared from impeachment, after a historic vote in the Senate concluded he was not guilty on both charges.

While he is only the third US President in history to face the impeachment process, Mr Trump managed to keep the Republican Party largely unified and claimed exoneration on Thursday.

He proudly displayed hard copies of two US front pages at the National Prayer Breakfast with the headline “acquitted".

The polarisation in US politics and public theatrics are bound to worsen as the election season gets under way.

Mr Trump is running largely unchallenged in his own party while Democrats are in a bruising fight between the progressive and the moderate camps to pick a nominee.

If the first week is any indication, the battle could stretch out until the summer convention if no clear front-runner emerges.