WASHINGTON — A bipartisan group of leading senators has reached agreement on the principles for a sweeping overhaul of the nation’s immigration laws, including a path to citizenship for the 11-million illegal immigrants already in this country.

The deal also covers border security, non-citizen or “guest” workers, and employer verification of immigration status.

Although thorny details remain to be negotiated and success is far from certain, the development heralds the start of what could be the most significant effort in years toward overhauling the nation’s inefficient patchwork of immigration laws.

President Barack Obama also is committed to enacting comprehensive immigration legislation and will traveled to Nevada on Tuesday to lay out his vision, which is expected to overlap in important ways with the Senate effort.