is a rare word, but in Chinese it seems to mean "native" as in "native American", so I guess this means "naturalize" (or more literally, "nativize"). Note that is an (old) causative form (=). Assuming this is true, the basic structure of the sentence is:
> **()**
>
> = **()**
>
> On the (Asian) continent, the Japanese expatriates and the disarmed soldiers can ask the Soviet Union to **()**.
Where **()** is:
>
>
> =
>
> to naturalize themselves in Manchukuo/Korea and lead lives under the protection of the Soviet Union
So the sentence says the expatriates and the disarmed soldiers can stay in and live there forever _if they desire to do so_.