The republican-supported plan to eliminate the so-called marriage penalty passed yesterday but Senator Tom Harkin says it only helps rich couples. The Iowa democrat says each party offered a plan for relieving the tax burden on married couples.The democrat plan would have given much larger tax breaks to couples in the 30-thousand dollar range. In contrast, the democrat plan would give no tax relief to a married couple who made 200-thousand dollars a year, while the republican plan would give that couple more than 13-hundred dollars in tax breaks. Harkin says the republican plan gives 78-percent of the benefits to the wealthiest 20-percent of the taxpayers. Iowa Senator Chuck Grassley, a republican, voted in favor of the tax-cutting bill.