What Democrats could do about the threat of a third party candidate

 Third-party candidate? Democrats have reason to be concerned, but what should be the approach? If the race boils down to a Biden-Trump replay as it appears at this moment, what might work? Acknowledge an understanding of their concerns about the environment and civil and gender rights, but a vote for the third party would backfire on them.  It would be a  vote for Trump.  Be smart.  The vote for Nader in Florida in 2000 resulted in the defeat of a pro-environment possible president.  The vote for a green party candidate in 2016 defeated Hillary Clinton in a narrow race.. Trump gave wings and encouragement to white nationalists entering the political mainstream and the eventual overturning of Roe v Wade.  

National campaigns have consequences.  It is not just a matter of the heart. It is not just ""voting my conscience". It should be a strategic decision of choosing among candidates.  The decision should be based on which one has the power to come the closest to getting the job done that comes closer to desired results.  The road to hell and backfires can be paved by good intentions.

Watch what Trump supporters are doing as an indication of what they believe to be their best strategy:  Some recent examples.  The most cynical one was GOP congressional leadership bringing in RFK Jr to testify and give him national exposure his to his wacky ideas of science and of conspiracy theories.  Jill Stein, Green Party, may be full of good intentions, but she was given support and sat near Putin at a dinner in 2016.  She became a Putin tool as part of the Russian interference in the 2016 election. 

Elections also have international consequences and it can be argued that the election of Trump led directly to a renewal of Russian expansionism and war, not to peace.  Putin dangled Trump Towers Moscow construction permits early in Trump's campaign for the nomination and Trump tried to damage NATO and questioned whether the Baltics and Poland were worth defending. Trump tried to use Zelensky as a political tool, denying anti-tank weapons in an attempt to force him to dig up or manufacture dirt on "the Biden crime family" and a personally flawed addicted human being of Hunter.  No wonder Putin thought that early in the Biden administration, the coast was still clear with a weakened NATO and a feeble old president to invade Ukraine and do it in three days.  It was a historical epic miscalculation, but it was the direct result of Trump's bootlicking foreign policy strategy he used in dealing with power-hungry foreign dictators and the painting of Biden as over the hill. Flattery not only got Trump nowhere, it caused Putin's miscalculation and almost gave hope that China could do it to Taiwan, too.  Trump's isolationism left a power vacuum our adversaries saw as an opportunity to fill.  It happened before, just as Hitler made the same miscalculation that the US would not get involved in his invasions of Europe and Russia,  and the Japanese saw the same military opportunity on the Pacific side.