Democracy vs justice

Iain Duncan Smith complains that "the government appears to have forgotten about the most vulnerable...750,000 more people have incomes below 40% of median income than a decade ago."
But is the failure here really New Labour's? Or could it be that democracy itself is an obstacle to social justice? There are two senses in which this is the case:
1. The very worst off are, by definition, a small minority. There are therefore few votes to be won from helping them.
2. Justice requires that we be disinterested - that we put ourselves behind a veil of ignorance and adopt the position of an impartial spectator. But politicians never ask us to do this. They only appeal to self-interest.
Perhaps, then, democracy itself is incompatible with justice, in the sense of helping the most vulnerable.
And it's not just this leftist conception of justice that democracy prevents us realizing. Maybe democracy is also incompatible with entitlement theories of justice; the perceived self-interest of the median voter often requires that the rich be taxed heavily.
John Rawls recognized one solution to this problem. His principles of justice, he said, should apply not to every political decision but to the "basic structure of society."
He was deliberately vague about what this exactly is. But one construal is that the principles be embedded within the constitution, so they are not vulnerable to passing political winds.
This raises several questions. One is: is this another sense in which justice (however defined) and limited government are partners, not enemies? Another is: doesn't this suggest the case for a written consitution is more powerful than generally thought, as only this can protect the worst-off?

Comments

[Rob Spear]

Where are you going to get the legitimacy to institute a written constitution except through the democratic process? Especially in this day and age.

[james higham]

...the case for a written consitution is more powerful than generally thought, as only this can protect the worst-off?...

How can a constitution protect the worse off economically, Chris?