Democratic and Republican Approaches to Social Security

Democrats want to raise the income ceiling to pay in, while Republicans want to means test payments. In other words, Democrats want to tax labor (since social security contributions are determined by labor income), while Republicans want to tax capital (since most of the recipients’ additional income, which would be subject to means testing, is income from capital, either directly or indirectly). So, remind me again: which party is the workers’ party, and which is the capitalists’ party?