It's almost impossible, now, to imagine any country being able to execute a surprise to the degree of Pearl Harbor against the United States. I know the reasons usually given for Japanese success - ships were conveniently grouped together, radar readings were faulty, it was a Sunday, etc.
But a large part of the reason it's hard to imagine another Pearl Harbor is because the US massively outspends and outclasses just about everyone else in terms of weaponry. Is there any evidence that the Japanese military was "better" than ours, in the way we think of it now?
I don't think you'll find much argument against the position that the Japanese navy, in most respects, was militarily superior to the USN at the start of World War II. Japan was quite aware it did not have the industrial or financial resources to win a prolonged war against the U.S., which was seen as a potential adversary for most of the interwar period; instead, Japan's navy specifically trained for what we'd now consider asymmetric warfare, becoming proficient in fighting at night, using the then-new technology of airplanes and aircraft carriers, and emphasizing fewer but larger weapons systems that could overwhelm a quantitatively larger opponent. And this worked for them in at least the first six months of the war -- they overran allied (Australian/British/Dutch/American) forces in conquering the Philippines, breaking the Malay Barrier, raiding into the Indian Ocean and driving the British fleet to the far side of the subcontinent, and pushing a defensive perimeter all the way out to New Guinea in the south, Burma in the west and the Gilberts in the east. They lost this momentum after strategic mistakes at the Battle of the Coral Sea and the Battle of Midway, collectively two battles where all of their fleet carriers were disabled, and the Americans were able to take the strategic initiative with the invasion of the Solomon islands (Guadalcanal being the focus of the struggle), but it was not until 1944 or so when the American building program provided overwhelming force that would eventually win the war.
