????上周早些時候，達(dá)沃斯世界經(jīng)濟(jì)論壇（the World Economic Forum）一開幕,，就有人開始議論紛紛：全球金融精英齊聚一堂,，諸多國家元首及財政部長紛紛亮相，美國代表團(tuán)成員的級別卻明顯較低,。沒有財政部長,，沒有國務(wù)卿。當(dāng)然也沒有國家元首,。

????其次是這樣的情況：奧巴馬總統(tǒng)在上周一發(fā)表的第二次就職演說中,，著重提到的是大量的國內(nèi)問題，而對于是否打算在第二個任期內(nèi)在國際上發(fā)揮自己強(qiáng)有力的領(lǐng)導(dǎo)才能方面,，卻沒有什么表示,。約翰霍普金斯大學(xué)高級國際研究學(xué)院（Johns Hopkins University School of Advanced International Studies）院長、前奧巴馬政府高級官員瓦利?納斯?fàn)柋г拐f：當(dāng)美國內(nèi)部辯論占據(jù)主導(dǎo)地位時,，“有些人就會想當(dāng)然地認(rèn)為可以暫停對國際事務(wù)的關(guān)注或參與,。”

????將上述兩個情況放在一起考慮,，世界經(jīng)濟(jì)論壇的與會者不由得提出這樣的問題：奧巴馬的軍事干預(yù)政策曾被一位顧問形容為“幕后領(lǐng)導(dǎo)”,，現(xiàn)在他是在有意識地放棄美國在世界經(jīng)濟(jì)中占據(jù)的領(lǐng)導(dǎo)地位嗎？如果是這樣的話,，是否有任何一個能力遠(yuǎn)遠(yuǎn)不及美國的國家來填補(bǔ)這個空缺呢,？

????上周四早上，倫敦對此做出了回答——英國首相戴維?卡梅倫走上了講臺,，嘗試扮演這個角色,。卡梅倫剛處理完阿爾及利亞的一起導(dǎo)致至少37人死亡的恐怖襲擊事件。他在上周四早上的演講中宣布,，我們正在“與兇殘的恐怖主義進(jìn)行一場長期的斗爭”,。

????不過，卡梅倫特別顯示出領(lǐng)導(dǎo)權(quán)威的是在經(jīng)濟(jì)方面,。英國首相卡梅倫上周三宣布,，計(jì)劃與歐盟就英國保留歐盟成員國地位的條件進(jìn)行談判，比如嘗試減少對企業(yè)的監(jiān)管約束,，然后讓英國選民通過公投來決定他們是否仍然想繼續(xù)保留歐盟成員國的地位,。許多歐洲領(lǐng)導(dǎo)人及一些英國企業(yè)老總對他的這番言論仍然感到震驚。

????不過,，上周四卡梅倫還利用一個不同的身份——即作為今年八國集團(tuán)輪值主席的身份——大膽直言,。卡梅倫宣布,，他將利用自己這個身份,，“聯(lián)合全歐洲大陸積極促進(jìn)企業(yè)釋放活力?！彼赋?，英國已削減了企業(yè)所得稅稅率，減少了監(jiān)管約束,，并且向發(fā)展中經(jīng)濟(jì)體派遣了龐大的經(jīng)貿(mào)代表團(tuán),，向他們傳遞了“英國重新提倡貿(mào)易開放”的信號。

????他說,，現(xiàn)在他計(jì)劃著手解決企業(yè)逃稅和避稅問題,，推動經(jīng)濟(jì)體系向更加公平，更具競爭力的方向發(fā)展,。 他說：“如果一家企業(yè)不繳納應(yīng)該繳納的稅款,，其他企業(yè)最終就等于是繳納了更多的稅款。一部分奸商對經(jīng)濟(jì)體系玩花招時,，所有企業(yè)都會因他們的名譽(yù)受損而遭受不利的影響,。”

????美國的表現(xiàn)與此形成了鮮明的對比,，美國共和黨和民主黨議員（以及白宮）只是空口答應(yīng)了要對企業(yè)所得稅進(jìn)行改革——以此承諾會提高美國的國內(nèi)生產(chǎn)總值,，并且把海外資金吸引到美國國內(nèi)用以本土投資。

????奧巴馬喜歡攻擊企業(yè)的避稅行為,，這在競選過程中發(fā)揮了很好的作用?？穫悇t在履行一個使命：點(diǎn)燃推動經(jīng)濟(jì)增長的火箭引擎,。他大幅降低了英國的企業(yè)所得稅稅率，而現(xiàn)在才開始打擊企業(yè)鉆空子的不法行為。

????The murmuring started as soon as the World Economic Forum opened here earlier this week: In this gathering of the globe's financial elites, featuring heads of state and finance ministers, the U.S. contingent was remarkably low level. No Treasury Secretary. No Secretary of State. And certainly no Head of State.

????Then there was this: President Obama's second inaugural address, given Monday, was heavy on liberal domestic issues, light on signs that he intended to exercise strong leadership abroad in his second term. "There is an assumption that you can push the pause button" on foreign affairs while internal debates dominate, complained Vali Nasr, dean of Johns Hopkins University School of Advanced International Studies and a former top Obama administration official.

????Put those two together, and WEF attendees were asking: Was Obama, whose military intervention policy was once described by an adviser as "leading from behind," consciously ceding the American position as economic world leader? And if so, was any other country remotely equipped to fill the void?

????On Thursday morning, the answer came in from London: British Prime Minister David Cameron stepped up to the podium to audition for that role. In his Thursday morning address, Cameron -- fresh from handling a terrorist attack in Algeria that left at least 37 dead -- declared that we are in a "long struggle against murderous terrorists."

????But it was on the economic front that Cameron especially showed muscle to charge ahead. European leaders, and some UK business chiefs, were still reeling from the Prime Minister's Wednesday announcement that he planned to renegotiate his country's terms of membership in the EU -- seeking to reduce regulation on business, for example -- and then let British voters decide if they still wanted to be part of the union.

????On Thursday, though, Cameron spoke out in a different role -- as president of this year's G-8. In that capacity, Cameron announced an "aggressive, pan-continental drive to unleash enterprise." Already, he noted, the UK has cut the corporate tax rates and reduced regulation, and sent huge trade delegations to growing economies with the message that "Britain is back open for business."

????Now, he said, he plans to tackle corporate tax evasion and avoidance, to make the system fairer and more competitive. "When one company doesn't pay the taxes they owe, then other companies end up paying more. When some cowboys play the system all businesses suffer the fall-out to their reputation," he said.

????Contrast that to Washington, where both Republican and Democratic lawmakers (and the White House) have given only lip service to corporate tax reform -- which holds out the promise of boosting GDP and bringing offshore capital back home for U.S. investment.

????Obama is fond of attacking corporations for tax avoidance; it plays well on the campaign trail. Cameron is on a mission to light the rocket engines under economic growth: He dramatically reduced his country's corporate tax rate -- and only now is going after the loopholes.