The United States has been on a collision course with Iran well before the Islamic Revolution of 1979. We often cite 1979 as a starting off point of hostilities because there is an easy event to wrap our minds around. In this case, the deposition of the Shah and the storming of the American Embassy in Tehran.
However, the initial American deposition of democratically-elected Prime Minister Mohammad Mosaddegh and forcing Shah Mohammad Reza Pahlavi into power in 1953 really began this collision course.
With only a handful of exceptions, this has largely been a cold war conflict. The bulk of the fighting has been through proxies and cyber-attacks. The way Iran responded to the killing of General Qassem Suleimani, by not killing any Americans, is only further proof of this cold war status quo.
The Iranian military has strengthened itself significantly ever since the Iran-Iraq war ended in the late eighties. With little doubt, Suleimani has been integral in shaping Iranian influence in the region. The toppling of Sadaam Hussein and the lack of stable government to replace him in Iraq has led to a massive vacuum that was quickly filled by Iran and a conniving Suleimani. Again, we see further American inability to be forward thinking in a region filled with problems.
Since 1979, Iranian actions in general, and Sulemani’s in particular, have shown what their intentions are. The United States has been engaged in this cold war conflict with Iran for over forty years; however, malicious actions have been taking place for far longer.
Therefore, this question of whether President Trump declared war on Iran by striking at the top is irrelevant. The question we should be asking is whether this escalation is worth the price we may pay. Any honest expert would quickly admit that it is impossible to know what may come of this in the long term. Americans tend to have short term memory, while Iranians will remember every slight.
Iran is terrified of the United States. Do not mistake their loud barks for a fierce bite. Whatever bite they exact can still hurt, especially to an American public that has no more desire after years of conflict in a regional quagmire. If they were not scared, they would have struck immediately, and not had a convenient three-day mourning period where they can benefit from public support and time to think. Of course, that is simply a guess. But guesses are all that we have.