Getty/Photo Montage by Salon Now that the 2018 campaign season is truly underway, mainstream media chatter about the "blue wave" narrative is about to become cacophonous. To be clear, there are lots of reasons for optimism. Donald Trump's presidency has inspired a widespread mood of resistance and motivated political organizing to an extent that it's no exaggeration, for once, to call "unprecedented." Progressive boots are hitting the ground, progressive hands are knocking on doors and progressive wallets are opening up, funding both Democratic candidates and progressive organizations. But it would be unwise for those on the left to get too complacent about their certainty of a blue wave.