It’s no longer a matter of when but how Jacqui Lambie will leave the party that delivered her one of the most decisive (and divisive) roles in today’s polity.

Back in 2013, with minimal experience in party politics and a fast-diminishing campaign war-chest, Lambie had her heart set on getting into the Senate despite having unsuccessfully tested the waters with Labor and been rejected by the Liberals.

The offer from cashed-up Clive Palmer to join the Palmer United Party’s Tasmanian Senate ticket must have seemed almost too good to be true.

And so it has been. Lambie may have ridden on PUP’s short-lived swell into the Senate – a feat she would not have achieved in her previous incarnation as an independent candidate – but since becoming a minor celebrity due to her pivotal membership of the Senate crossbench, the new Senator has quickly outgrown the limits of party solidarity.

Lambie has been agitating about her right to speak out on matters of interest, even if not necessarily of interest to PUP, ever since she arrived in Canberra. Various thought bubbles have ensued, starting with the one on mandatory national service for young Australians and most recently the even more controversial call to ban the “burqa”.

In response, Palmer has evolved from commenting that Lambie is entitled to express her own views, to having to reject some of her suggestions such as the call for a “silent protest” at Remembrance Day ceremonies.

Lambie has consequently been unhappy that party solidarity is not a two-way street, even though according to Palmer the Senator appears to have made no effort to bring those issues to the party room for discussion or to determine a PUP position.

Whether she’s perceived as behaving like a petulant teenager, or a passionate defender of those she represents, Lambie is ratcheting up the pressure on Palmer to throw her out of PUP. (Or her senior adviser is doing so, depending on the extent to which one believes Rob Messenger is Lambie’s David Oldfield or Svengali.)

Earlier this week Lambie delivered on her commitment to oppose all Government legislation until the ADF pay decision is overturned, and split from her party to vote against the revised social services bill. She also voted against anti-doping legislation that in other circumstances she says she would likely have supported.

Today’s news that Lambie will join Labor and most of the crossbench Senators to disallow the FOFA regulations continues that war of attrition. In voting to disallow the regulations, Lambie will directly oppose a deal her party leader made with the Government.

If Lambie had been a Labor member, voting against her party in this way could be grounds for expulsion. However, the Coalition is somewhat more flexible on such matters, with Malcolm Turnbull and Barnaby Joyce being two high-profile examples of Coalition MPs having crossed the floor against their parties and not only survived but been appointed to Cabinet.

There is no question that Lambie will soon be an independent member of the crossbench. Over past days, the Senator has removed the PUP logo from her website, refused to attend PUP meetings, chosen to sit away from her party colleagues when attending the joint meeting of the Parliament, and removed all trace of yellow from her wardrobe.

In turn, Lambie has essentially been excommunicated from PUP: cut from the list of PUP MPs on the party’s website, removed as the party’s deputy Senate leader and deputy whip, and (in a classic case of shutting the gate after the horse has bolted) suspended from attending party meetings.

In short, Lambie is daring Palmer to sack her, while he in turn is trying to make her leave. This manoeuvring is all about who can position themselves as the victim once the split has taken place. Lambie wants to be sacked, firstly so she doesn’t have to break a previous commitment made to Palmer to stay, but more importantly so she can continue to claim underdog status.

Palmer however didn’t come down in the last shower. The canny operator is biding his time, putting pressure on Lambie to leave by isolating her and her staff from the party, while offering empty platitudes so that he can capitalise on what would be her broken commitment to stay and paint himself as the wronged party.

This will be important if Palmer follows through on a suggestion made last weekend that he will pursue Lambie with lengthy and expensive legal action if she leaves.