Affordable housing, homelessness and mental health. For mayoral contenders Peter Ladner and Gregor Robertson, the path to Vancouver's mayor's chair leads straight through these hot-button issues.

A debate focused on these issues will be held tonight at St. Andrew's-Wesley United Church on Burrard at Nelson. Doors open at 6:30 pm.

Tonight's debate is presented by the Homelessness and Mental Health Action Group at St. Andrew's-Wesley United Church, and co-sponsored by 24 Hours and TheTyee.ca.

And the event is free – unlike this morning's $790-per-table debate being sponsored by a certain daily newspaper. (Among the questions posed at this morning's 'Sun debate: "What is your favourite color, and why?")

Both candidates have tried to position themselves as the best able to squeeze funding from senior governments. But both have also been cautious in offering policies about what the city itself can do.

"We have a health crisis on our streets right now," said Robertson of the centre-left Vision Vancouver party. "The city's ability to solve that is very limited. But we can crank up the pressure to make sure people are looked after."

Ladner, of the centre-right Non-Partisan Association, insists Vancouver has done more for housing than any city in the country.

"At some point we have to recognize that the city cannot do this alone," Ladner said. "This problem cannot be solved on the backs of the city taxpayers."

Irwin Loy reports for 24 Hours.