 -- Bernie Sanders brushed off Donald Trump's latest criticism of the self-proclaimed democratic-socialist today, but used Trump's salvo that he's "going to tax you people at 90 percent. He's going to take everything," to raise an issue central to his campaign -- income inequality.

"If I had to respond to every absurd thing that Donald Trump says, I'd spend my whole life doing it," Sanders, the Vermont senator running for the Democratic nomination for president, told George Stephanopoulos on "This Week" Sunday.

"Trump raised that issue –- let's talk about it," he added of his what his tax policies would be if he were elected president.

Sanders is perhaps best known in political life for his efforts to champion the middle class, saying that in order to bridge the widening wealth and income inequality gap in America, the country needs a revamped tax policy that forces Wall Street, big corporations, millionaires and billionaires –like Trump – to pay up – and doesn’t impose further taxes on the middle and working class.

However, when pressed by Stephanopoulos about whether the proposed Senate tax legislation he backs, which would use a payroll tax to fund a mandate for 12 weeks of paid family and medical leave from all U.S. employers, Sander confirmed that the bill would require taxing all citizens -– not just the top 1 percent.

"[The payroll tax] would hit everyone –- yeah, it would. But it would mean we would join the rest of the industrialized world and make sure that when a mom has a baby she can in fact stay home with that baby for three months, rather than going back to work at the end of one week," Sanders said.

"We are the ... only major country on earth that doesn't guarantee paid family and medical leave," he added.

Sanders said his tax policies would primarily aim to close tax loopholes that let the rich evade taxation, raising the estate tax, and taxing Wall Street speculation, the latter of which would fund his proposal for tuition-free public college and university education.

"We've got to address the fact that the middle class in this country is disappearing, they need help," Sanders said. "We have massive wealth and income inequality -- the wealthy are going to have to pay more in taxes."

MaryAlice Parks contributed to this reporting.