The V2 was decidedly continental with a range of 320 km (200 mi). That would be considered "tactical" under present nomenclature. ICBM is considered for ranges in excess of 5,500 km (3,400 mi).
The first successful ICBM was the R-7 Semyorka (NATO: SS-6 Sapwood), with an 8,800 km (5,500 mi) range. Flight testing began in 1957, and the design was operational by 1958. A modified R-7 launched Sputnik 1, in October, 1957.
I'm not arguing that further development of specific innovations didn't proceed to a high degree in the United States.
But the question regarding Japan was innovation vs. copying. The Unites States, until at least the late 19th century, and arguably well into the 20th, was copying at least to a significant degree. You might care to acknowledge this point.
Your point that countries "[n]eed a free market to enable people to profit from improvements" may have greater merits, though that too seems arguable.
<https://en.wikipedia.org/wiki/Ballistic_missile#Types>
The first successful ICBM was the R-7 Semyorka (NATO: SS-6 Sapwood), with an 8,800 km (5,500 mi) range. Flight testing began in 1957, and the design was operational by 1958. A modified R-7 launched Sputnik 1, in October, 1957.
<https://en.wikipedia.org/wiki/R-7_Semyorka>
I'm not arguing that further development of specific innovations didn't proceed to a high degree in the United States.
But the question regarding Japan was innovation vs. copying. The Unites States, until at least the late 19th century, and arguably well into the 20th, was copying at least to a significant degree. You might care to acknowledge this point.
Your point that countries "[n]eed a free market to enable people to profit from improvements" may have greater merits, though that too seems arguable.