周一，中东小国阿曼本该感到心惊肉跳。特朗普总统警告阿曼，不得阻挠美国在霍尔木兹海峡的行动。他在接受福克斯新闻采访时放话：“如果阿曼从中作梗，我们就狠狠轰炸他们。”
但阿曼对此并未过分紧张，这也情有可原。
原因在于，特朗普过去反复告诫世人，总统若是发出威胁却不兑现，会招致严重后果。可近几个月来，他自己已经发出大量空洞的武力威胁。
事实上，在伊朗战争问题上，特朗普似乎奉行一套策略：大肆放出武力警告，却并无真正付诸实施的强烈意愿 —— 即便他当初或许是认真的。
而正如过去的特朗普本人会指出的那样，这种做法会造成一个后果：阿曼这类国家会越来越不愿顺从美方要求，因为它们不相信美国总统真的会说到做到。
伊朗显然就持这种态度。
到如今，特朗普在伊朗战争中虚张声势已是不争的事实。近四个月前我就撰文提到，战争开打才不到两个月，特朗普就已经对伊朗发出五次威胁，但全部没有落实。
每一次威胁都附带明确诉求与最后期限，可每到关头，特朗普都取消了扬言要发动的打击。
这并不是因为伊朗满足了他的条件，往往是特朗普声称，局势出现乐观迹象，协议马上就要达成。
当然，事后证明每一次的乐观预期全部落空。
这看上去更像是特朗普单纯想给自己的威胁找台阶下。这些威胁包括要摧毁伊朗文明、打击其基础设施（这有可能构成战争罪行）。
自此之后，这类看似虚张声势的警告还在不断增加。
举例来说，7 月 22 日特朗普宣称，只要伊朗袭击霍尔木兹海峡的一艘船只，“美国就会轰炸并摧毁伊朗一座桥梁或者发电厂”。
此后阿联酋多次指责伊朗袭击阿布扎比国家石油公司所属船只，但没有迹象显示美国按照警告报复打击伊朗基础设施。
特朗普还多次暗示要对伊朗发动大规模打击，却没有提出具体条件，这类攻击至今并未落地。再加上美军弹药储备不足，外界甚至怀疑美国是否有能力实施这类大规模军事行动。
这里还有一层战略层面值得考量：外界无从知晓全部幕后谈判细节，但伊朗十分清楚特朗普多次在威胁上退缩。没有证据表明，特朗普收回威胁时，伊朗已经快要接受美方条件，但伊朗心知肚明，特朗普对于谈判进展的描述存在不少夸大成分。
就算伊朗确实给出过谈判有望成功的信号，可最终始终没能达成一份可持续的协议，这本身就很能说明问题。按理来说，到某个节点，美国总统应当拿到实实在在的成果，才会选择让步。
特朗普偶尔也提到，伊朗或许在刻意哄骗美国，伊朗的承诺不可信，但他依旧没有放弃谈判。
特朗普威胁的效力受损，还有一个简单原因：不光是伊朗战事，他平时就动辄发出大量武力警告。
第二任期的特朗普并不吝于动用美国军事力量，迄今为止已经在七个国家发动打击，伊朗是最新一例。
这确实会让阿曼担心，如果拒不服从最新要求，自身可能遭遇不测。但绝大多数打击针对的并非各国政府，而是恐怖组织。
而且特朗普发出过打击威胁的国家，数量比实际动手的还要多。阿曼是第七个遭到威胁、却尚未遭到打击的国家，另外还有加拿大、哥伦比亚、古巴、格陵兰（属于丹麦）、墨西哥、巴拿马。
算上这些，特朗普第二任期内，要么发动过打击，要么发出过打击威胁的国家，占到全球国家总数的十三分之一。
其实早在周一之前，阿曼就已经被特朗普威胁过。今年 5 月，特朗普就说过和周一十分相似的话。
“阿曼必须安分守己，和其他国家一样，不然我们就得把他们炸平。” 特朗普当时说道。
显然那次威胁并没有达到预期效果，于是特朗普又追加了一次警告。
不过两次威胁都没有对应阿曼实际做出的特定行为，因此很难评判阿曼是否满足了他的诉求。
但曾经有一位美国总统会告诫特朗普：发出威胁，就务必做好兑现的准备。那个人，就是昔日的特朗普。
他过去经常痛批前总统奥巴马划定叙利亚红线 —— 禁止叙利亚对本国国民使用化学武器，可叙利亚越过红线之后，奥巴马却没有采取行动。
2016 年共和党全国代表大会上，特朗普称这件事是 “屈辱”，因为 “全世界都明白这条红线毫无分量”。
2017 年，他评价这是 “空洞的威胁”，让美国在世界其他地区蒙受损失。
到 2018 年，特朗普高调宣告美国外交开启新时代。
“今天的行动释放一个重要信号：美国不再发出空洞威胁。我许下承诺，就一定会兑现。”
这番话是他退出伊朗核协议时所说。可自那以后，他不仅发出一大堆空洞威胁，还把这套手段变成对伊政策的核心手段。
Trump’s TACOs on Iran loom over his big threat to Oman
Monday should be a very scary day for the small Middle Eastern country of Oman． President Donald Trump warned it against interfering with US efforts in the Strait of Hormuz， telling Fox News， “If Oman gets in the way， we’ll bomb the sh＊t out of them．”
But one could forgive Oman for not getting too hot and bothered．
That’s because Trump， a president who once warned repeatedly about the dangers of presidents failing to follow through on their threats， has made lots of empty ones in recent months．
Indeed， Trump seems to have embraced a policy in the Iran war centered on firing off threats that he doesn’t seem terribly inclined to enforce — if he ever actually meant them．
The problem with that， as a former version of Trump would have pointed out， is it makes countries like Oman less likely to comply with his demands， because they don’t necessarily think Trump is willing to make good on them．
Iran has certainly adopted that posture．
Trump’s track record of bluffs in the Iran war is undeniable at this point． Nearly four months ago， I wrote about how Trump， even at that early juncture less than two months into the war， hadalready made five threats against Iranthat he failed to follow through on．
All of them involved a specific demand and a specific deadline． Each time， Trump called off the threatened attack．
But it wasn’t because Iran actually gave him what he wanted； it was instead often because Trump said there wassome other reasonfor optimism about a deal being right around the corner．
Of course， that optimism proved unwarranted each time．
It wound up looking a whole lot like Trump simply wanted an off－ramp from his threats， which have included ending Iran’s civilization or striking at its infrastructure （a potential war crime）．
And the apparent bluffs have continued to mount since then．
For example， Trump on July 22 said that for every Iranian attack on a ship in the Strait of Hormuz， “the United States will bomb and destroy ONE BRIDGE OR POWER PLANT．”
The United Arab Emirates has since thenblamed Iran for repeated attacksonAbu Dhabi National Oil Company vessels． But there’s no indication that Trump has targeted Iranian infrastructure in retaliation．
Trump has also repeatedly teased massive attacks on Iran without making specific demands． But those attacks have yet to materialize． And there are questions about whether the United States can even afford to launch them， given theshortfalls in its munitions stockpile．
And there’s a strategic aspect worth considering： While Americans aren’t privy to all the behind－the－scenes negotiations， Iran will know plenty about just how much Trump has truly caved on these threats． There has been little evidence that Iran was actually that close to agreeing to anything when Trump backed down from his threats， but Iran would know how much Trump was embellishing about the supposed progress．
Even if they did give Trump some reason for optimism about a deal， the fact it never actually led to a sustainable one would seem instructive． At some point it’d be logical to think the US president would insist on something tangible before he backed down．
（Trumphasoccasionally referenced the idea that Iran might be leading him on and that its word simply can’t be trusted． But he hasn’t given up on negotiations．）
The effectiveness of Trump’s threats also suffer from another simple fact： He simply makes a lot of them， even outside the context of the Iran war．
Trump has shown he’s plenty willing to throw US military might around in his second term — launchingstrikes in seven countries so far， with Iran being the most recent．
That could certainly give Oman concern about what might happen if it failed to comply with his recent demand． But most of these strikes weren’t against the government in power， but rather terrorist groups．
And Trump has actually threatened or left open the possibility of striking even more countries than that． Oman is the seventh country he’s threatened without actually striking， at least not yet， along with Canada， Colombia， Cuba， Greenland （which is part of Denmark）， Mexico and Panama．
Combined， that means Trump has attacked or threatenedone out of every 13 countriesin his second term．
And Oman was in that category even before Monday． Back in May， Trump said something very similar to what he said Monday．
“Oman will behave just like everybody else，or we’ll have to blow ‘em up，” Trump said at the time．
It seems that threat hasn’t had the intended effect． So Trump just tossed another one on top of it．
Though neither one was tied to a specific Omani action， so it will be hard to judge whether Oman truly gave him what he wanted．
But there is one US president who might advise Trump that， when he makes such threats， he had better mean them． That would be the Trump of yesteryear．
He regularly pilloried former President Barack Obama for setting a red line — that Syria couldn’t use chemical weapons on its own people — and then failing to act when Syria breached that line．
In his 2016 Republican National Convention speech， Trump labeled it a “humiliation，” because “the whole world knew it meant absolutely nothing．”
He in 2017 called it a “blank threat” that cost us “in many other parts of the world．”
And by 2018， Trump defiantly rang in a new era in American foreign policy．
“Today’s action sends a critical message： The United States no longer makes empty threats，” Trump said． “When I make promises， I keep them．”
Trump made that comment when he pulled out of the Iran nuclear deal． Since then， he’s not only made a bunch of empty threats， but he’s made them a cornerstone of his Iran policy．
