大家知道这句英语是什么意思么

mber

纽约时报今天的一篇文章，文章最后几句：

“It would appear that incidents involving China and other claimants have increased,” Mark Valencia, a maritime analyst in Hawaii and a leading expert on the dispute, said in an e-mail interview. “But why now — that’s the $64,000 question.”

With regard to China, he said, the answer is “perhaps, in part, because they can.”

that’s the $64,000 question是啥意思呀？
because they can是指中国能什么呀？
通读整篇文章好几遍联系上下文还是没弄清楚

原文地址：

http://www.nytimes.com/2011/06/11/world/asia/11vietnam.html?_r=1&ref=asia

bbmoz

the $64,000 question是个俗语，表达“这是个很难回答的问题”，底下那 because they can我觉得是指，前文说为什么是现在爆发了争执，从中国这方面来讲是因为他们有了争执的资本（应该包括前面提到的海南岛潜艇基地等等）。

猪头三

One reason the dispute has flared in recent years is that the 2002 accord has proved to be toothless, Michael Vatikiotis, a security expert at the Center for Humanitarian Dialogue in Singapore, said in a telephone interview.

China’s neighbors have grown increasingly uncomfortable as the People’s Liberation Army Navy has opened a submarine base on Hainan Island, and has ranged across the South China Sea.

二楼的笔友解释得很好；要回答“because they can”可以看上文的“2002年的协议没有toothless（没有强制性/无法律效力）”，还有上一段文中提到的“中国的邻居们越来越感到不安是因为PLA在海南岛的潜艇基地可以让其潜艇纵横捭阖。”
所以“部分原因是因为中国可以（递爪子了）”