When politicians describe their opponents' positions, they typically make those positions seem implausible and unattractive.
Conclusion (should = opinion)
Politicians could persuade more voters with their arguments if they simply followed the scholars in charitably formulating their opponents' positions.
Evidence
When scholars try to make an opposing position seem as plausible and attractive as possible (when they formulate it as charitably as possible), it makes their argument more persuasive to their colleagues.
Evaluate
Since this argument is based on a Comparison, we try to think of salient differences in order to object that the comparison is a shaky one.
For example, suppose we said,
We could think of a salient difference: wait a sec, even though taking a full-length LSAT practice is depleting, the recovery time is much faster than for a runner who runs a 26-mile practice run.
So when it comes to politicians and scholars .... can we think about any salient difference for why the advice of "portray your opponents' arguments as persuasively as possible" would hold for the latter but not for the former?
Goal
Look for an answer possibly saying that even though presenting opponents' arguments charitably makes scholars look good to their colleagues, it still isn't a good idea for politicians to do (since it would make their political rivals seem more level-headed and worth listening to, which is usually the opposite of a politician's objectives).