It's likely that historians will determine that tough, vexing votes on crucial, make-or-break issues defined the 112th Congress.

Eleventh-hour votes to avert a government shutdown. A vote to prevent an unprecedented federal default.

In addition, there are votes pending to avoid yet another closure of the Federal Aviation Administration, a vote to stave off yet another government shutdown and the much-anticipated vote to trim $1.5 trillion in spending as ordered up by the supercommittee sometime in December.

But a potential vote is looming which could dwarf all of those issues and make an immediate impact back in the districts and states of lawmakers.

All politics is local. And it doesn't get any more local than lawmakers deciding whether to mothball 3,700 post offices, halt Saturday delivery and possibly terminate universal mail service to far-flung places in Alaska, Montana and Maine.

Of course, there's a way lawmakers could sidestep such an agonizing vote.

Instead, they could just vote to introduce a direct appropriation from the federal treasury to help fund the U.S. Postal Service. That's something the Postal Service has done without since 1971. Or, Congress could directly cough up a $5.5 billion payment to prevent the layoff of 120,000 workers and short-circuit a possible default on the retirement funds of postal employees.

It's a classic Catch-22. Votes to name post offices are one of the easiest votes lawmakers take in the House and Senate. But lawmakers could find votes to close post offices as onerous as voting to raise the debt ceiling or casting a ballot for TARP (the controversial Troubled Asset Relief Program approved in the fall of 2008).

To be clear, Postmaster General Patrick Donahoe told a Senate hearing Tuesday that he doesn't want a rescue measure from Congress. Donahoe just wants lawmakers to grant him the agility to take the necessary steps to shutter little-used facilities and cut jobs.

"The Postal Service requires radical change to its business model if it is to remain viable in the future," said Donahue.

Sen. Tom Carper (D-DE), who heads a panel which oversees the Postal Service, agrees with Donahoe that changes are a necessity.

"No business facing the kinds of difficulty that the Postal Service faces today would survive for very long if it were told how many retail outlets it should have and where they should be located," Carper said.

Which is the root of the problem.

When it comes to big defense contracts, so-called "Beltway Bandits" are well-known for spreading out the construction of weapons systems and aircraft across multiple Congressional districts and states. In the 1980s, Rockwell International famously dispersed the subcontracting process for the construction of the B-1 bomber across 48 states and some 400 Congressional districts. Each of those subcontracts represented jobs. That made the B-1 "local" for lawmakers of all political and geographical stripes.

In Washington-speak, this is referred to as the "Iron Triangle." Strategically distributing the wealth assures the political viability of the contract.

But America's military industrial complex is child's play compared to how post offices are sprinkled across the country. And lawmakers will fight to protect their post offices in their districts and states. They'll cite the economic consequences of job losses. They'll argue how rural post offices are essential to serve their constituents who aren't fully integrated onto the digital grid. Some will invoke Norman Rockwell-esque notions which portray quaint, country post offices as the glue that binds communities together. Some may even romance letter writing.

Sen. Claire McCaskill (D-MO) suggested as much at Tuesday's hearing. The Missouri Democrat indicated that the Postal Service should consider an ad campaign that implores Americans to send more heart-felt letters to loved ones.

On a pragmatic level, Rep. Mazie Hirono (D-HI), who's running for the Senate next year, announced a series of town hall meetings to discuss plans to close four post offices in Hawaii. Those include the Uptown Honolulu Post Office and Kapolei Post Office on Oahu, the Kalaupapa Post Office on Molokai and the Hanamaulu Post Office on Kauai.

Hirono is inviting her constituents to send their views on merits of these facilities to the Postal Service (by U.S. mail, of course) by the end of the month in an effort to salvage them.

Hundreds of lawmakers are expected to mirror Hirono's effort to redeem post offices on the chopping block in their districts and states, too.

These are hard decisions for lawmakers.

Starting in the late 1980s and running through 2005, Congress faced a similar conundrum when it came to closing outdated or redundant military bases. In an effort to depoliticize the process, the government initiated the Base Realignment and Closure process (known as BRAC). Political considerations made it nearly-impossible for lawmakers to objectively yield many of their local facilities. So Congress empanelled the non-partisan, independent BRAC Commission to save money by composing its own list of bases to eliminate or restructure.

Congress still had the final say on closing the bases. But it decoupled politics from the decision-making process.

Still, BRAC offered Members of Congress an upside. Some lawmakers (especially those facing tough re-election fights) privately pined for their base to be targeted for closure. After all, that automatically gave the member a white-hot political issue to go to the mat over. It granted the lawmaker a chance to flex their rhetorical muscles and make a case for why voters should return them to office.

It's too early to say if the Postal Service will require a BRAC process to shutter some of its facilities. But it's clear that anything short of that could produce thousands of political brawls as lawmakers defend post offices on their own turf.

One should note two key facts amid the pending imbroglio over the future of the Postal Service.

It's likely many lawmakers will hue and cry about the chances of cutting off Saturday delivery. Interestingly, letter carriers delivered the mail seven days a week until 1912. Some post offices also served as meeting spots for churches on Sundays. So religious leaders lobbied to dial back delivery to six days.

In addition, the Postal Service now survives on business-generated revenue. Until the early 1970s, Congress helped subsidize what was then called the Post Office Department with an annual appropriation. Congress also designated postage rates. But the creation of the Postal Regulatory Commission de-politicized the process long ago.

"I have received no more than one or two letters in my life that were worth the postage," wrote Henry David Thoreau. That quote crystallizes the problem facing the Postal Service today. The digital age violently sliced into its market share. Online communication and private delivery services stripped the institution of essential revenue just as legacy costs for retirees began to skyrocket.

Lawmakers must now decide what to do about the Postal Service. They'll weigh the fates of stagnant post offices, jobs and community pride against a sea of red ink, to say nothing of their own electoral futures.

It's hard for lawmakers to vote against the interests of their district or state.

All politics is local. And it doesn't get any more local than the post office.