Second Edit: For a Radical, Long Dead/For Dawn Fraser, a Radical

[Achebe]

For a Radical, Long Dead

I
My dear dead poet,
you would be more important
if you were
an ancient red vase.

Then people would ponder your cracks,
debate the significance of your colour,
and label you an artifact.

II
You chose the losing side.
So now, on dusty shelves,
in boxes at garage sales,
next to cookbooks at thrift stores,
your verse sleeps. ...... 'verse sleeps' is too passive, and suggests a temporary, rather than permanent, rest. I'd prefer 'you are discarded'. 

A second death,
the worse way time can punish a person.  ... ineffective hyperbole. Most people who live are never remembered by the wider world. How is having your verse read and then discarded worse than what happens to most people?

III
Oh capital, 
he would think you the new devil, ... capital has been around since the dawn of civilisation, so I doubt if it's 'new'. Most likely, he already had a view on it.
pricing souls and convincing others
of your necessity.

Oh capital,
the victor of a war,
long lost.

Oh capital,
invisible monster
that chased me from my home.  

I don't see how the third part links to the first two. It's almost like two separate poems.
I thought at first that 'capital' was a pun on 'Kapital', and you were actually slighting Marx as a 'poet' instead of an 'economic theorist'. However, the narrator is complaining about capitalism as an 'invisible monster', so the pun on 'Das Kapital' does not work, unless the first two 'capitals' are with a 'C', and the last with a 'k', shifting the meaning from capitalism to communism through its foundational work.