Since when has it become a tradition for Australian Prime Ministers, let alone heads of minor Australian political parties, to be invited to or attend US Presidential inaugurations?

I tried unsuccessfully to find an answer to this on the all-knowing google. The only clue I got was from a wiki site on Obama's first inauguration: "Invitations and tickets were sent to ambassadors and chiefs of diplomatic missions to the United States and their spouses, but not to other representatives of foreign countries." This makes sense, within foreign countries (eg the USA) our ambassadors are the appropriate representatives at such events.

Do PMs and heads of Australian political parties attend the swearing in of any other heads of state, or prime ministers, In England, Canada, NZ, or China, France, Germany, or Russia??

I accept attendance at royal coronations, since the monarch of Britain is still formally our head of state. Mind you, the US presidency is becoming a bit like royalty, with inheritance rules: Bush 1, Bush 2; Clinton 1, Clinton 2 (failed), Trump 1, and who knows, he's got a lot of kids!

If you know, please post weblinks!

PS It was quite proper and intelligent of Pauline Hanson to decline, especially when the PM was not invited. If she had gone, it would have been held against her forever, and that would have damaged any future cooperation between her party and the Trump administration.
I'm not a supporter of Pauline, but I do think this was an astute decision on her part.

OP, "What do posters think?"

The inference could be taken that there is something unusual or odd and certain dignitaries from around the world have been slighted.

Nothing could be further from the truth. It is all the usual, traditional diplomatic etiquette. That is confirmed later in the featured article and should have been quoted perhaps.

Cossomby's observations (above two posts) are spot on.

Australian Prime Ministers as far as I know have not
in the past attended US Presidential inaugurations.
Chiefs of Diplomatic Missions in Washington are
the ones that are usually invited.

Here is a quote from the United State Department:

"The US State Department has advised that as in the
past, foreign delegations will not be invited to
Washington for the President-elect Trump's 2017
inauguration and the heads of state and governments will
be represented by Chiefs of diplomatic missions in
Washington," a DFAT spokesman said.

What prompted my starting this discussion was the
surprising fact that despite this statement Pauline Hanson
being neither a head of state or government or a
chief of a diplomatic mission received an invitation to
the inauguration. I thought this would make for an
interesting discussion. Especially as to why this invitation
was issued to her? Could it be because she drank champagne
in front of Parliament House when Mr Trump got elected
and pursued to express her admiration for the man, including
sending one of her senators to meet Mr Trump?

Whereas here are what some Australian politicians had said
about Mr Trump in the past:

http://www.abc.net.au/news/2016-11-09/what-australian-politicians-have-to-say-about-the-us-election/8007748

Given the State Department organises the inauguration and follows diplomatic protocol, I wondered whether Pauline had really been invited or whether this was just another example of fake news.

It turns out Pauline wasn't personally invited, as herself, or as leader of One Nation. The invite was a private one by a US politician to Malcolm Roberts. It was passed onto Pauline when Roberts declined. So she was doubly wise to also decline, who wants to go and get possibly bad publicity when you weren't even the one they wanted in the first place!

http://www.news.com.au/finance/work/leaders/how-one-nation-scored-an-invite-to-donald-trumps-inauguration/news-story/62d021a34a56a2ffcb88c511e3cb0615
"But still, when One Nation leader Pauline Hanson revealed yesterday she had been invited to come along to the historic event on Saturday, we all wanted to know, how did she get on the list?

Ms Hanson won’t be attending the party due to “commitments in Australia”, but she’s sending a proxy.

One Nation NSW Senator Brian Burston will be attending in her place, and in his first public comments following his acceptance of the unusual invitation, the mystery surrounding how it ended up in the minor party’s hands was revealed.

In an interview with ABC radio, Mr Burston revealed the invitation was delivered via the office of Republican congressman Adam Kinzinger.

According to Mr Burston, Mr Kinzinger reached out to One Nation staffer Darren Nelson, an economist who once worked for Mr Trump and now advises One Nation Senator Malcolm Roberts.

The invitation, according to Mr Roberts, was initially intended for the Queensland Senator but he said couldn’t due to health issues, specifically a hernia. The invitation was then forwarded to Ms Hanson."

cont'd ...

I've finally found the link that explains how One Nation
scored an invite to Donald Trump's inauguration.
It's worth a read:

http://www.news.com.au/finance/work/leaders/how-one-nation-scored-an-invite-to-donald-trumps-inauguration/news-story/62d021a34a56a2ffcb88c511e3cb0615