Labor won’t be too unhappy that Liberal powerbroker Michael Kroger has confirmed the Victorian Liberals are open to a preference deal (in Kroger’s terms,  a “loose arrangement”) with the Greens because leader Richard Di Natale isn’t a “nutter”, and Di Natale saying he wouldn’t rule out supporting a minority Coalition government.

Both are, in a way unexceptionable statements — a Liberal-Greens “deal” would involve open preferencing by the Greens — e.g. not formally directing preferences to Labor. Antony Green estimated back in 2011 that this tends to reduce the Greens preference flow to Labor by 3% of preferences (not 3% of the vote). That is, in a very tight contest, it might make a difference, but otherwise it probably wouldn’t. And Di Natale’s comments indicated he’d probably back a Labor government — “it’s much more likely that the opportunity rests with Labor,” the Greens leader said. But under Christine Milne — by implication a “nutter” in Kroger’s estimation — the Tasmanian Greens supported a Liberal government in Tasmania in 1996.

Labor has been working hard to portray the Greens under Di Natale as drifting rightward. The Greens deal with the government on tax secrecy and, particularly, on Senate voting reform, have elicited near-hysterical reactions from Labor, with Sam Dastyari leading the charge. It was Dastyari who accused the Greens of “selling out tax transparency for a cheap, dirty deal with Scott Morrison”, and he wanted to crowdfund a billboard attacking the Greens on the issue. More recently, he used the Senate voting reform bill to theatrically accuse the Greens of selling out the Clean Energy Finance Corporation. Dastyari permanently looks on the verge of self-parody, but as Joe Hockey and Mathias Cormann discovered, he can be a dangerous enemy.

That Labor votes with the government against the Greens on a regular basis, rather than once or twice, doesn’t tend to get mentioned by Labor.

Now Anthony Albanese, a target for the Greens in inner-suburban Sydney, is spruiking a “secret deal”. Any preference arrangement, however loose, and even a bland statement that Di Natale wouldn’t completely rule out supporting a Coalition government will be more grist to that particular mill (and, again, it’s not like Labor hasn’t preferenced against the Greens to its own detriment in years gone by — hello, Steve Fielding).

For all that, it’s important to remember that the Greens have done well under Di Natale: there was no dip in the party’s support after he replaced Christine Milne, and the Greens have continued to poll at around 10% in the Essential Report, despite Di Natale having far less experience and profile than Milne. In polling terms, there’s been an almost seamless transition between leaders, which didn’t happen when Milne replaced Bob Brown — the departure of the veteran Tasmanian caused a dip in the Greens’ vote, but it began recovering before the 2013 election (before a stunning performance by Scott Ludlam in the WA Senate byelection).

The problem is, the Greens need every vote — even with an ordinary half-Senate election this year, there are six Greens senators up for re-election, and in Tasmania they no longer have Christine Milne’s name recognition. The 2010 election delivered an exceptional outcome for the Greens in unusual circumstances — extraordinary levels of disillusionment with both an opposition led by Tony Abbott and a Labor Party that had knifed Kevin Rudd. Di Natale is thus leading them into what will be, even under the best circumstances, a tough election where there are likely to be casualties in the Senate, even if they can jag another seat in the Reps.

Expect a lot more talk of “secret deals” from Labor, and more stunts from Dastyari.