What is an example of how Cassius manipulates Brutus?

I would argue that Cassius is not able to manipulate
Brutus.  He attempts to manipulate him through flattery and even some bullying, but it
seems to me that Brutus is the one that gets his way.  Two important places where Brutus
overrides Cassius are in Act II, scene i, when the conspirators meet and Act III, scene
i when he insists that Antony be allowed to speak at Caesar's
funeral.

In Act II, scene i, first Brutus repudiates
Cassius' suggestion that they "swear [their] resolution" to murder Caesar.  Brutus has
quite a long response to this in which he asserts that they are Romans and, as such,
have no need to swear.  It is their honor that will create their bond.  And then, more
crucially, when Decius Brutus suggests that they murder Antony too, Brutus puts the nix
on that as well:

readability="13">

Cassius

Let
Antony and Caesar fall
together.

Brutus

Our
course will seem too bloody, Caius Cassius,

To cut the head
off and then hack the limbs...

For Antony is but a limb of
Caesar.

This, along with
Brutus overriding (once again) of Cassius after the murder of Caesar and permitting
Antony to speak at the funeral, could be argued as the two fatal mistakes to the success
of the conspiracy.  In Act III, scene i:

readability="11">

Cassius

You
know not what you do.  Do not consent

That Antony speak in
his
funeral...

Brutus

It
shall advantage more than do us
wrong.

Cassius

I
know not what may fall.  I like it
not.

Well, like it or not, it
is not Cassius that has the upper hand, much to his own frustration.  So, I would argue
that Cassius, try though he might, is not able to manipulate Brutus at
all.