????半年來，批評人士一直在嚷嚷說，伯南克的寬松政策會引發(fā)大規(guī)模通貨膨脹，導(dǎo)致美元貶值。隨著美元指數(shù)接近52周低點，通脹預(yù)期略有上升，拋售美元的論調(diào)近日有所升溫。

????但是，要是所有這些批評都錯了，美聯(lián)儲（Fed）尋求溫和通脹并不注定美元就是要貶值？要是事實上經(jīng)濟增長乏力對美元的影響更大呢？

????這很難說，因為外匯交易中有太多因素，從貨幣政策到貿(mào)易流，再到經(jīng)濟增長等等。但顯然，僅僅通脹上升并不意味著美元就會下跌。

????回顧過去25年，美元交易的兩個階段——1988年至2001年是美元上漲期，2001年至今是美元下跌期。

????你或許會以為后一個時期的消費者價格指數(shù)(CPI)漲幅可能較高。要求伯南克下課的呼聲以及對于食品和能源價格上漲的抱怨，當(dāng)然都指向于此——相反，90年代留給人們的記憶則是通縮型繁榮。

????但美國銀行（Bank of America）的經(jīng)濟學(xué)家伊桑?哈里斯指出，美元上漲期的CPI平均漲幅為3.2%，而此后為2.4%。所謂的“印刷紙幣可能造成不可挽回的影響”的論調(diào)，可以休矣。

????“如果(貨幣發(fā)行)從自律到‘貶值化’的轉(zhuǎn)變是在推高通脹，這一影響被其他因素淹沒了”，哈里斯寫道，“而且，如果批評人士是對的，美聯(lián)儲在加大美元貶值力度，為何過去幾年美元走勢平穩(wěn)？”

????當(dāng)然，部分原因是美元兌其他貨幣的匯率總是會有漲有跌，而歐元區(qū)近年來在金融穩(wěn)定方面也確實乏善可陳。

????但如果看一看美國的經(jīng)濟增長率（90年代增長強勁，近十年疲弱），你也可以為90年代美元的上漲和過去十年美元的下跌找到合理的解釋。即便現(xiàn)在，你也可以說，弱勢美元未能充分反映美國的增長潛力，特別是美元/日元匯率——在上周的匯率干預(yù)前，日元正在攀向新高。

????“美元并不經(jīng)常能因為美國經(jīng)濟增長而受到推崇”，MF Global外匯分析師杰西卡?赫文森表示。

????在這樣的情況下，盡管歐元區(qū)仍存在政治問題和紓困擔(dān)憂，歐元/美元處于52周高點。歐洲央行（European Central Bank）已表示，預(yù)計下個月將上調(diào)利率，為高漲的大宗商品價格降溫。

????眼看油價即將升至4美元/加侖，狡猾的央行銀行家們能有這樣的明確表態(tài)確屬罕見。但回想起2008年歐洲央行應(yīng)夏季油價大漲而上調(diào)利率后的結(jié)局，哈里斯表示，批評者在抨擊伯南克前最好先回顧一下去年歐洲的情形。

????“對于有些人而言，這證明伯南克在通脹方面是一個超級鴿派，”哈里斯寫道，“在我們看來， 這證明他對前景風(fēng)險的判斷優(yōu)于其批評者?！?/p>

????不過，這并不能說明太多問題。

????For six months critics have been screaming that Bernanke's loose policy would set off massive inflation and destroy the value of the dollar. Dump-the-dollar calls have picked up lately, with the dollar index near a 52-week low and inflation expectations rising a bit.

????But what if all the yelling is wrong and the Fed's pursuit of modest inflation doesn't doom the dollar? What if the dollar is actually more allergic to anemic growth?

????It's hard to say for sure because there are so many factors in currency trading, ranging from monetary policy to trade flows to economic growth. Yet it's clear that higher inflation alone doesn't mean a weaker dollar.

????Consider the two dollar trading regimes in the past quarter century: the rising dollar world of 1988-2001, and the falling dollar world since.

????You might assume consumer price inflation has been higher in the latter period. Calls to can Bernanke and complaints about higher food and energy prices certainly suggest this -- as does the memory of the 1990s as a disinflationary boom.

????Yet the CPI averaged 3.2% in the rising-dollar period and 2.4% since, Bank of America economist Ethan Harris says. So much for the supposedly irreversible dangers of printing.

????"If this shift from discipline to 'debasement' is increasing inflation, the impact is being swamped by other developments," Harris writes. "Moreover, if critics are right and the Fed is increasing its debasement of the dollar, why has the dollar leveled off in the last few years?"

????In part, of course, the answer there is that the dollar has to rise and fall against something, and the euro area is not exactly setting any financial stability records lately either.

????But you can also rationalize the dollar's rise during the 1990s and its fall during the past decade by looking first at U.S. growth, which was strong then and has been weak lately. Even now you could argue the dollar's weakness fails to appreciate U.S. growth potential – particularly vis a vis Japan's yen, which was hitting new highs before last week's intervention.

????"The dollar doesn't always get a lot of credit for the growth story here in the U.S.," says MF Global currency analyst Jessica Hoverson.

????To that end the euro, for all its political problems and bailout fears, is trading at a 52-week high against the dollar. The European Central Bank has signaled it expects to start raising interest rates next month, in a bid to cool rising commodity prices.

????In a world where $4 gasoline is coming soon, that sounds like a rare bit of clear-headed resolve from weaselly central bankers. But Harris, recalling what happened when the ECB raised rates in 2008 in response to that summer's oil spike, says detractors would do well to see how this latest inflation-scare movie turns out before bashing Bernanke.

????"For some, this episode is evidence that Bernanke is an über dove on inflation," writes Harris. "To us it is evidence that he is a better judge of the risks around the outlook than his critics."

????Not that that's saying much, really.