And so if you are the Klingons, you send a very risky mission that will certainly cause the feds to stop at nothing from destroying you. You used Pearl Harbor. Part of the decision used in favor by the Japanese military leadership to attack was because they thought they could destroy the US ability to respond in the short term (battleships and especially carriers) and a negotiated peace would be reached before they could. Also it was an isolated island... not the mainland with heavier defenses. Oceans aside, imagine if they had leveled the White House and congress, probably with the president in it. As I am sure the Fed president and council would be on Earth.
Of course it only enraged a nation into total war and didnt work out too well for the Japanese. You mentioned about Romulans getting involved. Just like Germany did and the war didnt work out so well for them either. So first, would the feds have only a small fleet or a reasonably sized one with moderate striking power... keeping in mind that Enterprise could level a planets surface by itself. If so, this attack would do nothing about the ability for a counter strike. So the question becomes would the Klingons think a devastating war is worth the risk. They are warriors but not idiots.
Anyways... things like this are interesting scenarios to consider. Besides, Roddenberry always tried to compare a Fed-Klingon war to a US-Soviet one. Not US-Japan. He was right.