Talks of a progressive alliance have been circulating ever since Theresa May called the election. And, on and off, for many years before that. Unsurprisingly, such calls persist after the election (see Caroline Lucas's article in the Guardian).
There are many reasons why this siren call will fall on deaf ears.
First, Jeremy Corbyn's Labour Party has not yet found its way to peaceful alliance within its own ranks. The idea that it could construct an alliance across four or more parties is simply not credible. Especially since one of those parties (the Liberal Democrats) fought the election promising no alliances, no coalitions.
Second, to call for a progressive alliance is to misunderstand the reasons for the relative success of the Labour Party in this election. Under Corbyn, the Labour party managed to present itself as a radical insurgent party. A party that wanted to break with the status quo and re-invent the country along radically different lines. Corbyn, a rebel his whole life, embodied those values. It was this platform of radical insurgency rather than stayed progressivism that energized voters - and especially the young. This reflects what we are seeing everywhere. Whether it is Trump in America, Macron in France, Podemos in Spain or the Five Star Movement in Italy, what is energizing the voters is the promise of radical change, a repudiation of the established status quo, and a leadership that visibly and credibly embodies all of that. Whether that change has its origins in what we used to define as the Left (Podemos) or the Right (Trump) doesn't matter a damn. It is the sometimes destructive, sometimes constructive vision of tearing down the establishment that is the only common feature of electoral success.
A British version of a progressive alliance would not be able to offer any of that. An endless series of compromises would be required for such an alliance to work. This would result in tedious plain vanilla - exactly what the voters are rejecting.
Ms Lucas suggests a couple of reasons to support such an alliance. The first is 'parliamentary arithmetic'. This is Westminster bubble thinking. Pragmatic though it may be, parliamentary arithmetic is hardly an energizing platform. The second is the well-worn 'anything to stop the Tories.' Again, this hardly qualifies as a bold vision capable of mobilising widespread support. After all, in spite of a disastrous campaign, the Conservative party was still the one to win the largest share of the vote.
A progressive alliance may be a way of providing an alternative majority in parliament. It may be the only way that Labour and other parties can shoehorn themselves into power. But an inspiring vision that will energise the British public it is not.