So, you're already telling everyone you don't understand the spoiler effect, basically advocating the opposition to assure their own loss.
Vote splitting is the most common cause of spoiler effects in FPP. In these systems, the presence of many ideologically-similar candidates causes their vote total to be split between them, placing these candidates at a disadvantage. This is most visible in elections where a minor candidate draws votes away from a major candidate with similar politics, thereby causing a strong opponent of both to win.
A spoiler campaign in the United States is often one that cannot realistically win but can still determine the outcome by pulling support from a more competitive candidate.
Any other bright ideas?
How do you suggest they do that? They're the minority in both chambers of congress & already overwhelmingly oppose the president's party on legislation. From roll call analysis
polarization is at the highest in the last several decades
Democrats have lately voted with higher party unity than Republicans
non-cooperation between parties is the highest it's been for at least 6 decades & increasing
They're supporting protests against the president's actions.