Mayor Rahm Emanuel is defending his tough-medicine cure for ailing public pensions in missives sent Wednesday to the employees who would take a financial hit.

In letters and emails to all city employees, Emanuel explains the goal behind his proposal to boost employee pension contributions, raise retirement ages and suspend cost-of-living increases applied to retirement benefits.

"If we follow along the current path, we know we will confront two stark choices: Either the city's pension payments will squeeze its ability to offer the essential services that you provide, or each of our pension funds will go bankrupt, leaving you and your families without retirement security," Emanuel wrote.