????美國國會的債務上限談判取得了期盼已久的突破，達成協議的希望越來越大了。協議達成后，美國將能夠提高債務上限并結束長達兩周的政府關門。雖然在美國財政部即將耗盡其舉債限額的前幾天，美國有望僥幸躲過違約的厄運，但這或許也只能為美國提供一個短暫的喘息機會。

????據《華盛頓郵報》（Washington Post）報道，美國參議院共和黨核心議員將于周二上午11點召開會議，審議已成形的協議。如果最終達成協議，美國財政部的舉債能力將延期至明年2月7日，美國政府也將重新開門。此外，它還能在1月中旬前為聯邦機構提供資金。幾個月之后，如果國會因債務上限再度陷入僵局，那也不足為奇。只不過下一次美國的運氣可能沒這么好了，至于為什么會這么說，看看最新的這次債務上限談判就很清楚了。

????與2011年標普（Standard & Poor's）調降美國AAA級信用評級時的政治僵局不同，這一次部分議員（尤其是共和黨議員）一直對此漠不關心。

????他們一直在淡化觸及債務上限的嚴重性。肯塔基州參議員蘭德保羅表示，美國可以專門預留資金來償付債券持有人，從而避免違約。這種說法乍一聽有點道理，但實際上意味著其他政府支出就沒有保障了，包括向社保金領取者的付款。這種情況很恐怖，因為要維持良好的財務狀況，靠不付賬單顯然行不通。

????對美國政府來說，逃避財務義務將對美元造成非常嚴重的影響。

????加州大學經濟學家巴里?艾肯格林在博客網站Project Syndicate上發表了一篇文章，討論了全球儲備貨幣美元違約會產生的影響，即：美元大幅貶值以及金融機構嚴重虧損。

????艾肯格林說：“即使美國財政部優先償付債券持有人，也就是選擇先把承包商和社保金領取者晾在一旁，美國國債投資者也不再會理所當然地認為美國政府肯定會還錢的，他們會認真考慮了。”

????事實上，各國中央銀行已經對全球最富有的國家美國失去信心了，他們正在采取預備措施，防范美國會像部分人士擔心的那樣隨時違約。美元一旦下跌，影響會波及全球，小國貨幣的匯率將紛紛出現暴漲。同時，新興市場經濟體也將受到打擊，因為韓元和墨西哥比索等新興市場貨幣會大幅升值，導致它們出口海外的商品價格更貴，競爭力更低。

????后果聽起來十分嚴重，但華盛頓的某些政客對此并不買賬，這也不難理解。次債危機發生后，市場普遍預計美元會大跌，但實際上根本沒跌。艾肯格林表示，隨著投資者瘋狂買入美國國債避險，結果美元倒還出現了上漲。一年后，雷曼兄弟（Lehman Brothers）破產了，不過美元依舊毫發未損。

????但他指出，如果美國違約，對美元的影響會截然不同。違約發生后，經濟中流通的現金將出現嚴重短缺，因為美聯儲（U.S. Federal Reserve）用于在金融機構之間轉移資金的電子網絡無法結算違約證券交易。回購市場以及由美國國債作為抵押擔保的貸款將會凍結。

????In a long-awaited breakthrough, Congress is inching closer to a deal that would increase the nation's borrowing limit and end a two-week-old government shutdown. The U.S. may just barely miss a default days before the U.S. Treasury exhausts its ability to borrow, but the sigh of relief could be short lived.

????As the Washington Post reports, the Senate's Republican caucus is scheduled to meet at 11 a.m. Tuesday to consider an emerging deal, which if finalized, could extend the Treasury's borrowing power until Feb. 7, reopen the government, and fund federal agencies through mid-January. Months from today, it wouldn't be surprising if Congress stalls over the debt ceiling again. Only next time the U.S. may not be so lucky, and the latest debt ceiling debacle offers a good glimpse as to why.

????Unlike during the political gridlock in 2011 when the U.S. lost its stellar credit rating from Standard & Poor's, some lawmakers (Republicans, in particular) have been downright blasé about it all this time around.

????They've been playing down the significance of hitting the debt limit -- Sen. Rand Paul of Kentucky says the U.S. can avoid default by putting aside funds to pay bondholders. That may sound fine at first, but it effectively suggests other expenses, such as payments to Social Security recipients, could take a back seat. That would be scary because not paying your bills obviously isn't a good way to get yourself in good financial condition.

????And for the U.S. government to skip its financial obligations would be catastrophic for the U.S. dollar.

????In an article in Project Syndicate, University of California economist Barry Eichengreen lays out the implications of a default on the world's reserve currency. The result would be a sharp drop in the dollar combined with huge losses for financial institutions.

????"Even if the Treasury paid bondholders first -- choosing to stiff, say, contractors or Social Security recipients -- the idea that the U.S. government always pays its bills would no longer be taken for granted," says Eichengreen, who writes frequently about the demise of the dollar. "Holders of U.S. Treasury bonds would begin to think twice."

????Already, the world's central banks are losing faith in the world's richest country; officials are preparing for a U.S. default some say could happen at any time. The dollar's decline would be felt across the world, causing the value of smaller currencies to spike. It would also hurt emerging market economies, causing currencies from South Korea to Mexico to shoot up and therefore make whatever they sell abroad more expensive and much less competitive.

????This sounds pretty awful, but it's easy to see why some folks in Washington aren't convinced. When the subprime-mortgage crisis hit, it was widely forecast that the greenback would tank, but that never happened. Eichengreen notes the dollar actually strengthened as investors scrambled for safety in U.S. Treasury bonds. That also happened a year later when Lehman Brothers went under.

????But a default would be different, he argues. There would be a serious shortage of cash circulating the economy, as the electronic network operated by the U.S. Federal Reserve to transfer funds between financial institutions isn't set up to settle transactions in defaulted securities. The repo market, loans offered against Treasury bonds, would freeze up.