CHICAGO (STMW) — When former West Side state Rep. Derrick Smith was arrested in 2012 for accepting a $7,000 bribe, he swore to the FBI that he “did it for the people.”

That’s the same reasoning federal prosecutors used Monday, asking that Smith receive a “a significant period of imprisonment” that “vindicates his constituents.”

“When a public official blatantly violates the most basic principles that he promised to uphold, there must be consequences,” the feds wrote in a sentencing memo.

Smith, who was found guilty last June of shaking down a day care business in return for a letter of support for a state grant, could face up to 5 years in prison.

The conviction came after a federal mole taped Smith accepting the bribe — a sum Smith obsessed about over a period of seven weeks and frequently referred to as “cheddar.”

Under FBI questioning in 2012, Smith — who had only recently been appointed to his seat — said he needed the cash for his campaign fund.

“He felt the whole West Side of Chicago was against him and [he] needed to do this (accept the cash) to keep his public office,” federal prosecutors wrote, dismissing Smith’s claim as “untruthful.”

Yet despite his initial brazenness, Smith eventually agreed that he “f***** up,” trial testimony showed.

In a dueling memo released Monday, Smith asked Judge Sharon Johnson to spare him jail time.

And he insisted the “seven stacks” of cash the FBI recorded him discussing went straight to campaign workers and “street money” — not his bottom line.

“Derrick Smith’s life is about serving the public and giving of himself,” his lawyers wrote in the memo. “Although this conviction has ended his political career, it has not ended his desire to continue to live a life of service.”

(Source: Sun-Times Media Wire © Chicago Sun-Times 2015. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)