Final answer:
Congress exhibited liberalism early in Nixon's presidency by expanding Great Society programs, such as removing the poorest from tax rolls, federalizing food stamps, and adjusting Social Security payments for inflation.
Step-by-step explanation:
An example of how Congress was liberal at the beginning of Nixon's presidency can be seen in the substantial expansion of Great Society programs despite Nixon's previous criticism of such policies. In 1969, he signed a tax bill effectively removing around two million of the poorest individuals from the tax rolls and expanded the food stamp program.
Additionally, Nixon supported the automatic adjustments for inflation of Social Security payments. This demonstrated Congress's willingness to uphold and enhance liberal economic policies that supported the poor and elderly, even under a Republican president with a conservative fiscal reputation.