WASHINGTON — Setting up a historic year-end debate, Senate Democratic leader Harry Reid unveiled his long-awaited version of legislation to reshape the nation’s health care system Wednesday night, a measure designed to extend coverage to 94 percent of eligible Americans and bar private industry from denying insurance because of pre-existing medical conditions.

"Tonight begins the last leg of this journey," said the Nevada Democrat, less than two weeks after the House approved its version — and nearly 10 months after President Barack Obama’s Inauguration Day summons to action.