WASHINGTON, D.C. ? Senate leaders have broken a two-week impasse on a major pension overhaul bill, allowing the House and Senate to begin talks on how to secure the future benefits of millions with defined benefit pension plans.

Under the agreement worked out by Senate Majority Leader Bill Frist and Minority Leader Harry Reid, Republicans will send nine senators to the House-Senate conference on the pension bill, and Democrats will send seven.

“We’re advancing a very, very important issue, one that is time-sensitive,” Frist said on the Senate floor. “The issue is so important to the 44 million out there who right now are working in an uncertain environment as we address this defined-benefit pension system.”

The goal is to send a bill to the president by April 15. Without new legislation by then, companies will have to use an old interest rate formula in calculating their funding obligations that could drive up what they owe to their funds.