The senator is right to say Donald Trump is trying to destroy the credibility of the American political system and is using lies so that he can run it unchallenged

If the Democratic party is to offer hope, grit and stamina for the battle ahead with Donald Trump, it needs leadership. In his Guardian interview Bernie Sanders, the Democratic-allied senator from Vermont, makes a strong claim to provide that to a party that is in its worst state since the 1920s. The stakes could not be higher. The senator rightly calls out the US president for attempting to destroy the credibility of the American political system – using lies so that he can run it unchallenged as well as unhindered by the moral obligation to exercise power in an informed way.

Mr Trump seeks authoritarian control of republican government and is exploiting the Republican establishment’s desire for power and the Democratic party’s disarray. Not only do the Republicans control both chambers of Congress but the Democrats today have just 16 governorships – almost half what they had in 2008.

If there is no change by 2020, when states next redraw their legislative and congressional districts on the basis of a US census, Republicans could gerrymander to ensure Trumpism dominates US politics. Hence it is good to see Mr Sanders call for Republicans to join hands in opposing Mr Trump. It’s not just Republicans who must change. The US senator is clear that the Democrats should become a bottom-up party again and reconnect liberals with the concerns of ordinary working Americans. This means the party has to consider how to prevent wages from sinking and prevent jobs from being exported. It needs to make the case to white-collar workers, who are frightened of being downsized themselves, that paying taxes to provide benefits for all is a necessary act for social stability.

It will require a political project that flattens America’s dizzying inequalities and stops the secession of the successful. Democrats should question why globalisation is producing a world economy in which an attempt by a nation to prevent the immiseration of its workers may result only in depriving them of employment. What Mr Sanders is saying is that Democrats should face the unpleasant truths about themselves, but not take those truths as the last word about America’s chances for happiness.

The Democratic party must have more agency and less spectatorship. Democrats made America more than just an economic and military giant. They showed the world their nation was also a force for good. Mr Sanders is helping us to remember that.