Reagan's cuts in marginal tax rates for the rich were essential to reviving a battered economy. They believe Gardner's theory is inherently more egalitarian, more likely to reveal that all groups are the same, than the single-number IQ model behind The Bell Curve. In fact, the opposite is true. Consider sex differences in intelligence. Of course, when you break down the overall IQ number into its multiple components, you find sex differences.
Women are generally superior at short-term memory, perceptual speed, and verbal fluency.
But it's extremely unlikely that all racial groups are identical on not just one, but all eight dimensions of multiple intelligence. That would be like expecting to flip a coin and have it end up on its edge eight times in a row. While that's bad news for the ideologues of empirical egalitarianism, it's good news for moral egalitarians. Because diversity of talents gives different groups different market niches to exploit. For example, black basketball players tend to be able to not only jump higher than whites, but also outthink them during the flow of the game.