Barack Obama and Sarah Palin are busy promoting their ideas for shaping the United States' future.

Obama, the Democratic presidential candidate, delivered a speech to a gathering of the American Association of Retired Persons that focused on saving Social Security, while Palin, the Republican vice presidential candidate, keyed her radio address on taxes and energy, USA Today's "On Politics" blog reported Saturday.

Obama suggested the Social Security system could be saved by removing payroll caps on those making more than $250,000 a year.

"It's a change that would start a decade or more from now, and it won't burden middle-class families. In fact, 99 percent of Americans will see absolutely no change in their taxes -- 99 percent," he said.

Palin praised the civic spirit of Republican presidential candidate John McCain and promised their administration would govern with a non-partisan spirit in the best interests of the entire nation.

"No one expects us to agree on everything. But we are expected to govern with integrity, good will, clear convictions, and a servant's heart. And I pledge to all Americans that I will carry myself in this spirit as vice president of the United States," she said.