Understatement of the day.

WASHINGTON (AP) — A raucous public debate over the nation’s flawed immigration system is set to begin in earnest this week as senators finalize a bipartisan bill to secure the border, allow tens of thousands of foreign workers into the country and grant eventual citizenship to the estimated 11 million people living here illegally.

Already negotiators are cautioning of struggles ahead for an issue that’s defied resolution for years. An immigration deal came close on the Senate floor in 2007 but collapsed amid interest group bickering and an angry public backlash.

“There will be a great deal of unhappiness about this proposal because everybody didn’t get what they wanted,” Sen. John McCain, R-Ariz., a leader of the eight senators negotiating the legislation, said Sunday. “There are entrenched positions on both sides of this issue.”