Caroline Lucas and Jonathan Bartley. Photo, Jon Bartley, Twitter.

And we’re off. The night before nominations open for next leader of the Green Party, Caroline Lucas and Jonathan Bartley announce they are running on a joint ticket.

Reactions among Green members – those not personally close to Lucas or Bartley (Sian Berry and Caroline Russell AMs both immediately welcomed the announcement) – was mixed.

Here’s some extracts from my Facebook feed last night, from (very) active members:

“Standing as co-leader even further reduces choice and opportunity for new people to get elected to a leadership position”

“If Bartley were running on his own he wouldn't have: Access to Caroline Lucas's Facebook and Twitter, Easy access to get articles in the Guardian, Caroline's supporter base. Which is why I feel that the leadership election has been rigged. It's almost like Green Party members have been whipped by Caroline to support Jonathan…. I just think this process stinks and the leadership election is now broken”

“Every time I hear 'progressive alliance' I hear the death knell of radical politics in the party. I hope I'm wrong.”

“Seriously consideirng [sic] my membership”

“It's a shame Caroline Lucas has decided to stand for Green Party leader- effectively killing the contest and inevitably preventing some truly fantastic candidates from standing. Just what the Green Party needs at its helm too- middle class white people. Because we don't have enough of those in politics.”

All this seems to be fairly representative of opinion on the ground – talk of ‘rigging’ and ‘ruining’ the contest. One member told me on Twitter they’re not going to bother voting.

When did members become beset by so much cynicism? I think a lot of the sentiment seen so far is, dare I say it, premature and slightly churlish. Here’s why:

Caroline Lucas and Jonathan Bartley have a right to stand. Many members – and the public - want Caroline to stand. The Greens need strong leadership now, after being somewhat in the wilderness (ideologically and practically) since Corbyn was elected. And Caroline’s candidacy is balanced by having someone who is competent but has less of a profile – Jon Bartley – running alongside her.

This doesn’t have to be a ‘coronation’. Members have a right not to vote for them. Other candidates should – and I hope will – stand. Given the sentiment so far, it’s likely that there’s a large chunk of the party that won’t back them. I’ve covered other potential candidates here – there are plenty of them, including some that haven’t even been mentioned yet. Sure, they might not have the visibility that Caroline has. But there are three months until the results are in to build that visibility. We do, however, need a very healthy debate about the purpose of the Greens when we aren’t the only left-wing party in town anymore – and that can still happen. It’s good to see the Lucas/Bartley candidacy making that an issue.

This is an experiment, and maybe one that’s worth giving a go. The Greens haven’t done co-leadership since scrapping Principal Speakers around 2008. It’s an exciting democratic model that’s worth drawing the best elements from – and it’s clear that the two candidates’ qualities complement each other: Caroline – high profile, Jon – highly organised.

The Greens need a leader – or team - who can build links with a newly left-wing Labour party. The party simply hasn’t done enough of this (though the reasons are perhaps complex). While this isn’t to endorse the campaign, no one can deny that Caroline is the best person to do just this – having spent the past six years working cross-party in Parliament. Building alliances is absolutely where efforts need to be in the new political context – focusing on the push for a fair voting system. Declaration: I work for the ERS, but that doesn’t discount the fact that PR is an absolutely central issue for building the kind of politics we want to see.

There’s a couple of caveats, here. They picked the right time for them to announce, but the wrong time for the good of the party. Had they announced in two or three weeks, it would have left time for other lesser known candidates to put themselves forward. And to get a bit of a following. Starting the leadership race with Caroline and Jon as the ready-made frontrunners isn’t particularly healthy when it comes to good democratic debate in the party.

But for those who are already saying they aren’t going to bother voting, come off it. There’s three months to go, and a whole month for other candidates to come forward. This party is full of talent. Some people are leadership material. And if members are angry about the prospect of a ‘Caroline coronation’, they can and will vote with their hearts and heads.

What this article is however, is a call for other candidates to come forward. Don’t think this is a done deal. The Greens are a democratic party, and should act like it – and that includes not throwing toys out of the pram because someone is standing who it’s thought will somehow ‘automatically’ win.

So have a little faith and optimism, Greens. If Caroline and Jon win, I’m sure they’ll be excellent. I’m sure there are others who would also be excellent. Either way, we’re opening a new chapter in the party. Let’s have the reasoned, grown-up and vibrant debate we deserve.