Sen. Jeff Merkley (D-Ore.) is demanding President Obama seek congressional approval for any postwar U.S. force in Afghanistan after the White House-mandated 2014 withdrawal deadline.
"Should the President determine the necessity to maintain [American] troops in Afghanistan" after 2014, "any such presence and missions should be authorized by a separate vote of Congress," according legislation proposed by Merkley on Wednesday.
Fellow Oregon Democrat Sen. Ron Wyden, along with Sens. Rand Paul (R-Ky.), Joe Manchin (D-W.Va.), Tom Harkin (D-Iowa) and Mike Lee (R-Utah) are all co-sponsors of the Merkley amendment.
Merkley's amendment, however, will not affect potential advise and assist operations conducted with the Afghan military by that U.S. postwar force, according to the legislation.
The amendment will also not impede White House or Pentagon authority to carry out counterterrorism operations against Taliban, al Qaeda and other militant extremist groups fighting in the country.
Timing of the amendment comes as Washington and Kabul continue to wrangle over the final language of a postwar deal.
On Tuesday, Secretary of State John Kerry admitted "mistakes" were made in postwar talks between Washington and Kabul, vowing to grant Afghan leaders more leeway in the final agreement.
That change is only the latest effort by American negotiators to keep U.S-Afghan postwar negotiations from falling apart, less than a year before all American combat troops are scheduled to withdraw from the country.
On Monday, a defense official told The Hill that a key meeting of top Afghan leaders on the Obama administration's postwar strategy for the country is still on track, despite a recent terrorist attack in the country's capitol of Kabul.
The location of the attack is where members of the Loya Jirga, an assembly of the country's most powerful tribal leaders, are scheduled to meet later this week to review the U.S. postwar plan.
That meeting to review the American strategy, known as a Bilateral Security Agreement (BSA), remains on schedule despite the attack, according to the defense official.
Recent news reports earlier in the week stated a White House apology would be a part of a U.S-Afghan postwar deal to allow American forces to remain in the country after 2014.
National Security Adviser Susan Rice on Wednesday flatly denied reports that President Obama is drafting an apology for the U.S. war in Afghanistan, as a way to lock in a postwar deal in the country.
"No such letter has been drafted or delivered. There is not a need for the United States to apologize to Afghanistan," Rice said during an interview with CNN.
"We have sacrificed and supported [Afghanistan] in their democratic progress and in tackling the insurgents and al Qaeda. So that [apology] is not on the table."