I think the phrase "grub for power" does a better job describing the partisan approach to gaining power and influence than the term "grab for power."
Grabbing at power implies an openly acknowledged play for personal gain.
The way the Modern Dialectician engages in discourse is underhanded.
As a noun the term grub refers to insect larva. You might find such grub in a dead carcass or dung heap. It also applies to consumption.
As a verb the term grub means to dig at the roots. A second meaning is to scrounge. A example is to grub a cigarette. A third meaning is "to lead a laborious or groveling life." (drawn from dictionary.com).
The "grubbing" does a better job conveying the techniques of the modern radical.
The term "radical" means roots. When I hear the word radical, I think of someone approaching an issue at a root level.
I see both a affirmative and negative version of radicalism. The negative version of radicalism is one in which the radical attempts to change society by attacking the roots of society. The positive version of radicalism focuses on strengthening the roots of society.
The verb "grub" (to dig at the roots) pairs up well with the negative sense of the noun "radical."
The sentence: "The radicals grubbed for power by attacking the roots of society" completes a metaphor about roots.