Sussan Ley passed a milestone this week.

While locked in a string of party room meetings and tense negotiations with Anthony Albanese over Labor’s hate speech bill, she surpassed eight months and eight days as her party’s leader.

This meant that, no matter what would subsequently happen, she lasted longer in the top job than Alexander Downer did during his tenure as the shortest serving Liberal leader.

Already facing rumblings about a possible leadership challenge towards the end of 2025, Ley won newfound respect from colleagues while criticising Albanese’s response to December’s Bondi beach terror attack. She barely stopped over the summer break, bashing the prime minister day after day over his failure to call a federal royal commission on the shootings, and claiming credit when Albanese eventually backflipped earlier this month.

But the damaging fallout from three Nationals senators crossing the floor in parliament on Wednesday has marked the beginning of the end for the country’s first female opposition leader.

Even if a challenge doesn’t eventuate in the next few days, many in her party consider Ley on borrowed time.

The Nationals leader, David Littleproud, blew up the Coalition over Ley’s decision to accept the resignations of frontbenchers Bridget McKenzie, Susan McDonald and Ross Cadell, insisting the agreement between his party and the Liberals was “untenable” with Ley as leader.

Ironically, that comment from Littleproud – delivered as Ley went quiet to mark the national day of mourning for the 15 people killed at Bondi beach – may have bought her some time, with some Liberals insisting the Nationals should not be allowed to force a change in their party’s leadership, even if they have effectively called the shots on several Coalition policies since the federal election.

With MPs not scheduled to return to Canberra until 3 February, Liberals may cool off long enough to allow Ley to fill the gaps on her frontbench and present a Liberal-only opposition at the opening of parliament.

Many were angry that the final weeks of the summer break were interrupted for the special sittings this week. Almost all were furious at the Nationals for taking the focus off Albanese and Labor, again.

A challenge against Ley is likely to eventuate whenever her conservative rivals, Angus Taylor and Andrew Hastie, agree on who should be the candidate. The party’s right faction needs to settle on its preferred candidate, with some moderates expected to fall into line on whomever they choose. Taylor is returning from an overseas holiday this week, while Hastie has pushed back on social media critics who say he sold them out by voting for the same contentious legislation the Nationals opposed.

Ley’s deputy, Ted O’Brien, and Victorian Tim Wilson were included in the early conversations about possible candidates for senior roles. Some colleagues have begun talking up the New South Wales frontbencher Melissa McIntosh as a possible deputy should Hastie, a West Australian, become opposition leader.

Even if they were not prepared to call time on Ley’s leadership just yet, many MPs who spoke to Guardian Australia are angry at how negotiations on the hate speech bill played out. Littleproud could face his own challenge in the months to come, just as One Nation eats away at the Coalition’s base. Pauline Hanson’s party is predicting more Nationals will defect over the course of the year.

Ley might have outlasted Downer’s short-lived leadership of the Liberal party, but just whether she survives long enough to pass the next hurdle – Brendan Nelson’s uninspiring nine months and 13 days – is seriously in doubt.