The increasingly strident calls by some politicians to either
tighten or scrap the controversial mining profits tax ignore
that the measure is working as it is supposed to.  The response
to the federal government's somewhat sheepish announcement that
the tax raised just $126 million in its first six months,
nowhere near the budgeted $2 billion, has been predictable and
unimaginative.  Fiddling with the MRRT to ensure it raises more
money ... would be a silly and self-defeating mistake for any
government, while scrapping it altogether means forgoing revenue
in good times.   The government has engaged in shifting the
blame to volatile commodity prices and the strong Australian
dollar to cover its embarrassment that the budget surplus it
promised on the back of the mining tax has evaporated.  The
Greens, which along with three independents, support the Labor-
led minority government, want to change the law so that it
raises more revenue.  Meanwhile, the coalition, which was never
in favour of the tax and is leadi