Substantive State aid law has a number of weaknesses. One is that a State suffers no sanction when it pays an illegal aid, because competitors find it hard to claimcompensation. There are questions about how much of an illegal aid should be repaid, and about when tax measures can be aid. If a measure is selective, it is automatically assumed that competition is distorted. The Commission should act only against significant distortions of competition, and should prohibi