And then there were 4. 

Mississauga South MPP Charles Sousa has officially launched his campaign for leadership of the Ontario Liberal Party.

The former banker gave up his post as Minister of Citizenship & Immigration this week to take a shot at the party's top job.

He told supporters in Mississauga Saturday morning "I want to be your jobs premier".

Sousa promised to work to attract investment in rural Ontario, support the auto sector, make immigration work better for the province & to fast-track mining in the Ring of Fire.

He also committed to easing gridlock & making sure taxpayers' are getting the best returns on their money.

Sousa vowed to have Metrolinx take over control of the TTC, an idea which has also been floated by the Progressive Conservatives.  The Mississauga South MPP says politics have gotten in the way of transit expansion.  He says "the result is a transit system in Canada's largest city that is decades behind the times".

Sousa also committed to building a high-speed rail network across Ontario, starting with a link between Hamilton & Toronto, & Toronto to Oshawa.  He says that will lay the foundation for an expansion from Windsor to Quebec City.

Sousa joins former cabinet ministers Sandra Pupatello, Glen Murray & Kathleen Wynne in the race for the Ontario Liberals' top job.

Eric Hoskins will join them soon, after giving up his job as Children & Youth Services Minister this week.

Gerard Kennedy, who has lost past runs at leadership of the provincial & federal Liberals will reportedly declare his candidacy on Monday.

Liberals have until November 23rd to enter the leadership race.  The new party leader will be picked January 25-27, 2013.