New SAT reading sample comprehension problem

Test Preparation SAT Preparation
1

Hi guys, I am reading the sample passage for the new sat and i have trouble understanding.

”Of the impeachment
process, it was Woodrow Wilson who said that “Nothing
short of the grossest offenses against the plain law of the
land will suffice to give them speed and effectiveness.
Indignation so great as to overgrow party interest may
secure a conviction; but nothing else can.”

could you help me understand this part?

2

cant seem to write a lot…

3

He is saying that you should only impeach very serious crimes because you want to make sure that you get enough votes for a conviction even from members of the same political party (as the accused).