I hope they get laughed out of the courtroom. If the government passed a law banning all state governments from funding ACORN, or banning ACORN from being able collect private donations, or capriciously yanking their tax exempt status, or something of that nature, then they'd have a point. But all the congress did is shut off the federal dollar grant money spigot, which no one person or group is entitled to. To argue otherwise inevitably leads to two conclusions that can not be allowed to stand:
1) Non-government entities funded at least in part by federally appropriated grants are entitled to that money as a protected right under the constitution.
2) The level of funding provided in a budget or awarded as part of a multi-budget year program can not be cut or reduced until the end of the program or budget under which the appropriation has been made.
It may even be possible to argue a step further that a level of funding could never be reduced or cut, regardless or budget years or program sunset declarations, once appropriated the entity as a right to that same level of funding for ever more or until the government falls. But even without taking it to that level, the 2 prior conclusions are idiotic in the extreme, flying in the face of all good sense and reason. No doubt ACORN will win the case.