Social Security is not a tax: Federal Insurance Contributions Act (FICA)
I do not remember the abbreviation for medicare, that is also not a tax.
Before you say it, I know it is not voluntary even thought the feds say it is and I also know that it effectively operates as tax on the bottom line.
Actually, they are indeed taxes. The distinction is that FICA and Medicare are considered to be payroll taxes. They are levied only on earned income, with only a few exclusions.
The federal individual tax that Romney is referring to is an income tax. There's also the corporate income tax.
And there's more: the federal gas tax, the utility taxes, etc. are considered excise taxes.
Social Security is primarily funded through dedicated payroll taxes called Federal Insurance Contributions Act tax (FICA). Tax deposits are formally entrusted to the Federal Old-Age and Survivors Insurance Trust Fund, the Federal Disability Insurance Trust Fund, the Federal Hospital Insurance Trust Fund, or the Federal Supplementary Medical Insurance Trust Fund which comprise the Social Security Trust Fund.
Federal Insurance Contributions Act (FICA) tax is a United States Federal payroll (or employment) tax imposed on both employees and employers to fund Social Security and Medicare —federal programs that provide benefits for retirees, the disabled, and children of deceased workers. Social Security benefits include old-age, survivors, and disability insurance (OASDI); Medicare provides hospital insurance benefits for the elderly. The amount that one pays in payroll taxes throughout one's working career is associated indirectly with the social security benefits annuity that one receives as a retiree. This has caused some to claim that the payroll tax is not a tax because its collection is tied to a benefit. The United States Supreme Court decided in Flemming v. Nestor (1960) that no one has an accrued property right to benefits from Social Security.