Journalist: Although a recent poll found that more than half of all eligible voters support the idea of a political party whose primary concern is education, only 26 percent would like to join it, and only 16 percent would be prepared to donate money to it.
Conclusion
It's unlikely that an education party is viable in the long run.
Evidence
You can't be a viable party unless you have at least 30% of voters prepared to support the party by either joining it or donating money.
Only 26% of people would like to join the education party, and only 16% would donate money.
Evaluate
In order for us to counter-argue that an education party could be viable, we'd have to come up with a way to say that they are meeting the required 30% threshold.
Some people might already be thinking of the "wiggle room" here -- if the 26% and 16% refer to different people, then they've already done it! 26 + 16 = 42%
The author is assuming that the 16% is a subset of the 26%.
If there were 100 voters, 26 were willing to join the education party, and 16 of those 26 would go another step and actually donate money to it.
But it's possible that 26 people are willing to join the education party, while others are not willing to join the party but support its causes enough that they'd consider donating money to it (sorta like me and the Green Party).
Goal
Look for an answer calling out the author's assumption that the 16% is smaller circle within the bigger circle of the 26%, or an answer raising the objection that these two stats might refer to different people, in which case the education party has met the 30% "join or donate" threshold for viability.