Mao Zedong once said that “political power comes from the barrel of a gun”. Whether his apostolic successor President Hu Jintao, visiting President Barack Obama this week in Washington, believes this line in Mao’s catechism is unclear. Completely clear, however, is that the People’s Liberation Army not only believes it, but is implementing it.

Systematic expansion of China’s strategic nuclear weapons; rapid growth in submarine and blue-water naval forces; substantial investments in anti-access and area-denial weapons such as anti-carrier cruise missiles; fifth-generation fighter-bomber platforms; and sophisticated cyberwarfare techniques all testify to the PLA’s operational objectives.

Western leaders have chattered for years about China as a “responsible stakeholder” enjoying a “peaceful rise”. This is the acceptable face Mr Hu will present. But just because the musclemen aren’t listed on the passenger manifest doesn’t mean they aren’t flying the plane. China’s Communist party remains unquestionably dominant, and the PLA is its most potent element.

During US defence secretary Robert Gates’s Beijing meetings last week, China tested its stealthy J-20 prototype combat aircraft. Many scoffed at the notion that Mr Hu seemed surprised when Mr Gates raised the test, and at the Chinese leader’s explanation that the timing was coincidental. Was the J-20 flight intended to embarrass Mr Gates and Mr Obama before Mr Hu’s visit, or was it a signal to China’s civilian leadership about who is really in charge? In truth, both seem likely.

Both Mr Hu and the PLA undoubtedly understand that China is dealing with the most leftwing, least national-security-oriented, least assertive US president in decades. This matters, because China will be influenced by its perception of US policies and capabilities. Mr Obama’s extravagant domestic spending, and the consequent ballooning of national debt, have enhanced China’s position at America’s expense. Indeed, the only budget line Mr Obama wants to cut, and has done with gusto, is defence.

Sensing growing weakness, therefore, it would be surprising if China did not continue its assertive economic, political and military policies. Thus, we can expect more discrimination against foreign investors and businesses in China, as both the US and European Union chambers of commerce there have recently complained. Further expansive, unjustifiable territorial claims in adjacent east Asian waters are also likely. While the Pentagon is clipping coupons and limiting its nuclear capabilities in treaties with Russia, the PLA is celebrating Mardi Gras.

Consider two other important issues: Taiwan and North Korea. When Beijing threatened Taipei in 1996, Bill Clinton sent two carrier -battle groups to the Taiwan Strait, showing US commitment to Taiwan’s defence. Does anyone, particularly in Beijing, believe Mr Obama would do anything nearly as muscular faced with comparable belligerence today? On the North Korean menace, meanwhile, Mr Obama is conforming to a 20-year pattern of US deference to China which has enabled a bellicose, nuclear Pyongyang.

Of course, if China sensed a US determined to maintain its dominance in the western Pacific, and ready to match its determination with budget resources, it might be dissuaded from its recent objectionable behaviour. More balanced, co-operative and ultimately productive relations would likely follow. On the other hand, if China is determined to increase its military strength regardless of Washington’s posture, that is all the more reason for America to ready itself.

China should take careful note: neither Mr Hu nor the PLA ought to assume that Mr Obama represents broader US opinion. There could be a different president two years hence, ready to reverse his agenda of international passivity and decline. Beijing can take advantage of Mr Obama for now, both because of his philosophical and leadership weaknesses. But so doing could cost them in the future, if America in 2012 goes to the next level in rejecting his failing policies.

毛泽东曾经说过“枪杆子里面出政权”。他的信徒兼继承者胡锦涛（本周正在华盛顿会晤美国总统巴拉克?奥巴马(Barack Obama)）是否信仰毛泽东思想中的这一信条，我们不能确定。但我们完全可以确定的是，中国人民解放军(PLA)不仅信，而且正在身体力行。

中国战略核武器的系统性扩张；潜艇与深海海军实力的迅速增长；对反航母巡航导弹等反介入与区域封锁武器的巨额投资；第五代歼击轰炸机平台；高端的网络战技术——所有这些都证明了解放军的作战目标。

西方领导人多年来一直喋喋不休地讨论中国是一个“负责任的利益攸关者”，正在“和平崛起”。胡锦涛将展现出的也会是中国为西方所接受的这一面。虽然暴徒的名字不在乘客名单上，但他们有可能是驾驶飞机的人。毫无疑问，中国共产党仍处于统治地位，而中国人民解放军是其最强有力的组成部分。

上周美国国防部长罗伯特?盖茨(Robert Gates)访问北京期间，中国试飞了歼-20(J-20)隐形战斗机原型机。许多人对盖茨提及试飞时胡锦涛表现出的吃惊、及其给出的时间安排只是巧合的解释嗤之以鼻。歼-20试飞是为了在胡锦涛访美前给盖茨与奥巴马一个下马威，还是在向中国文职官员领导层发出谁是真正掌权者的信号？老实说，两者似乎都有可能。

胡锦涛与解放军无疑都明白，中国正与数十年来美国最左翼、最不以国家安全为导向、最不果敢的总统打交道。这很重要，因为中国对美国政策与能力的认知将对其产生影响。奥巴马在国内支出无度、以及因此导致的国家债务膨胀，已增强了中国的优势、损害了美国的利益。事实上，奥巴马唯一想削减且已经兴致勃勃地在削减的预算，是国防预算。

所以说，已经觉察到美国日渐疲弱的中国，如果不继续推行其自信满满的经济、政治与军事政策，才会让人感到吃惊。故此我们可以预期，在华外国投资者与企业将会如同在华美国与欧盟(EU)商会最近所抱怨的那样，面临更多歧视。而且，中国有可能会对东亚邻近海域提出进一步扩张的不合理领土要求。当五角大楼正能省则省、在与俄罗斯所订立的契约中限制自身核能力的时候，中国人民解放军却正在庆祝狂欢节。

再考虑另外两个重要问题：台湾与朝鲜。当北京1996年威胁台北时，比尔?克林顿(Bill Clinton)派了两个航母战斗群前往台湾海峡，展示了美国保护台湾国防安全的承诺。有谁、尤其是北京有谁相信，如果今天面临类似的交战状态，奥巴马会做出类似的强硬举动？此外，在朝鲜威胁这点上，奥巴马正在遵循顺从中国这个已持续了20年的模式，而正是这种模式造就了一个好战的、拥有核武器的平壤。

当然，如果中国察觉到美国决心维持其在西太平洋地区的主导地位，并准备相应地增加预算资源，也许就会停止最近这种令人反感的行为。随之而来的，可能是更均衡、更具合作性与最终富有成效的中美关系。反之，如果中国决心不顾华盛顿的姿态，执意提升自身军事实力，那美国就更有理由做好准备了。

中国应保持谨慎：胡锦涛与人民解放军都不应想当然地以为，奥巴马代表美国的普遍观点。两年后美国总统可能会换人，并准备逆转他在国际上处于被动且日渐式微的议程。北京眼下可以利用奥巴马，是因为他的哲学观存在缺陷、且领导不力。但如果美国在2012年能更进一步，摒弃奥巴马的错误政策，中国这么做便有可能使其在未来付出代价。