Dozens of lawmakers and aides are so afraid that their health insurance premiums will skyrocket next year thanks to Obamacare that they are thinking about retiring early or just quitting.

The fear: Government-subsidized premiums will disappear at the end of the year under a provision in the health care law that nudges aides and lawmakers onto the government health care exchanges, which could make their benefits exorbitantly expensive.

Democratic and Republican leaders are taking the issue seriously, but first they need more specifics from the Office of Personnel Management on how the new rule should take effect — a decision that Capitol Hill sources expect by fall, at the latest. The administration has clammed up in advance of a ruling, sources on both sides of the aisle said.

(PHOTOS: Supreme Court upholds health care law)

If the issue isn’t resolved, and massive numbers of lawmakers and aides bolt, many on Capitol Hill fear it could lead to a brain drain just as Congress tackles a slew of weighty issues — like fights over the Tax Code and immigration reform.

The problem is far more acute in the House, where lawmakers and aides are generally younger and less wealthy. Sources said several aides have already given lawmakers notice that they’ll be leaving over concerns about Obamacare. Republican and Democratic lawmakers said the chatter about retiring now, to remain on the current health care plan, is constant.

(Also on POLITICO: Poll finds low Obamacare support)

Rep. John Larson, a Connecticut Democrat in leadership when the law passed, said he thinks the problem will be resolved.

“If not, I think we should begin an immediate amicus brief to say, ‘Listen this is simply not fair to these employees,’” Larson told POLITICO. “They are federal employees.”

Republicans, never a fan of Democratic health care reform, are more vocal about the potential adverse effects of the provision.

“It’s a reality,” said Rep. Pete Sessions (R-Texas). “This is the law. … It’s going to hinder our ability with retention of members, it’s going to hinder our ability for members to take care of their families.” He said his fellow lawmakers are having “quiet conversations” about the threat.

(Also on POLITICO: TOP 5 complaints about Obamacare)

Alabama Rep. Jo Bonner said the threat is already real, especially for veteran lawmakers and staff. If they leave this year, they think they can continue to be covered under the current health care plan.

“I’ve lost one staffer who told me in confidence that he had been here for a number of years and the thought of losing the opportunity to keep his health insurance on Dec. 31 [forced him to leave]. He could keep what he had and on Jan. 1 he would go into that big black hole,” said Bonner, who had already planned his resignation from Congress. “And then I’ve got another staff member that I think it will be a factor as she’s contemplating her future.”

Lawmakers and aides on both sides of the aisle are acutely aware of the problems with the provision. Speaker John Boehner (R-Ohio) and Senate Majority Leader Harry Reid (D-Nev.) have discussed fixes to the provision. Boehner, according to House GOP sources, believes that Reid must take the lead on crafting a solution. Since Republicans opposed the bill, Boehner does not feel responsible to lead the effort to make changes.

(Also on POLITICO: House GOP's new anti-ACA group)

The Affordable Care Act — signed into law in 2010 — contained a provision known as the Grassley Amendment, which said the government can only offer members of Congress and their staff plans that are “created” in the bill or “offered through an exchange” — unless the bill is amended.

Currently, aides and lawmakers receive their health care under the generous Federal Employee Health Benefits Program. The government subsidizes upward of 75 percent of the premiums for the health insurance plans. In 2014, most Capitol Hill aides and lawmakers are expected to be put onto the exchanges, and there has been no guidance whether the government will subsidize those premiums. This is expected to cause a steep spike in health insurance costs.

MORE VERY BARRY CARE