An exercise of the Spending Power with conditions (strings attached) is valid if:

(1) the spending program is in pursuit of the general welfare (courts generally defer to Congress in defining general welfare);
(2) any condition it includes is unambiguously stated so that the states can make a knowing choice;
(3) there is a relationship between the condition imposed and the purpose of the federal spending;
(4) the condition does not induce the states to violate some other provision of the Constitution and, therefore, be independently barred (consider this issue by asking whether a state could enact the condition on its own, in the absence of the incentive of a federal spending program, without violating the constitution); and
(5) the financial inducement offered by Congress must not be so coercive as to go beyond pressure and amount to a compulsion.