Bill Casey, the former Nova Scotia member of Parliament for Cumberland-Colchester-Musquodoboit Valley, announced Tuesday he will be seeking the Liberal nomination in his former riding for the next federal election.

"There are several reasons for my interest in re-entering politics, but the issue that has motivated me to act now is that I want to add my voice to those very credible people who are raising the alarm about the declining state of our parliamentary system," Casey said in a statement released Tuesday.

"I believe that those of us who have experienced this deterioration first hand have an obligation to speak out."

Casey made headlines in 2007 when he was kicked out of Prime Minister Stephen Harper's Conservative caucus for voting against his government's budget, claiming it broke the Atlantic Accord with Nova Scotia and Newfoundland and Labrador.

He ran successfully as an Independent MP in October 2008 and held the seat until April 2009, when he retired to take a high-profile provincial government job.

Casey said he got to know Liberal Leader Justin Trudeau "pretty well" after he was expelled from the Conservative Party.

"I was assigned a seat in the very back row, in the opposition side of the House of Commons, and it turns out Mr. Trudeau ended up in the next seat to me," he said in a phone interview Tuesday.

"I got to know him really well over many months and we talked about a lot of things and we've been in touch ever since. He's offered to help me raise money for some charities and different things I've done, so it wasn't like a lightening strike. It's more of an evolution to this program."

He said while he was originally elected as a member of the Progressive Conservative Party of Canada, that party no longer exists and the Liberal Party reflects his values.

"I'm just a little bit left on some things, a little bit right on others and right down the middle on some. I think that pretty much describes, I would say, the position of the Liberal Party," Casey said.

Since Casey's retirement in 2009, Conservative Scott Armstrong has held the riding of Cumberland-Colchester-Musquodoboit Valley.

Armstrong, who is Casey's former campaign manager, said in a statement Tuesday that he is disappointed with his one-time boss's decision to run for the Liberals.