Complex sentence: The Estonian government decided according to the Kellogg-Briand Pact not to use war as an instrument of national policy, given the overwhelming Soviet force both on the borders and inside the country--not to resist, to avoid bloodshed and open war.
Split into simpler sentences: The Estonian government decided according to the Kellogg-Briand Pact not to use war as an instrument of national policy. Given the overwhelming Soviet force both on the borders and inside the country, not to resist, to avoid bloodshed and open war.