Translated from the original Hebrew (1927) by Rabbi Dr. Louis Ginzberg, as published in The Respona of Professor Louis Ginzberg, (ed. D. Golinkin, 1996). First published in Festival Prayer Book (ed. M. Farbridge, 1927).
Various iterations of an interpretative translation, whose authorship is not clear, can be found in Conservative siddurim and mahzorim published from 1927 until today, alongside a slightly altered Hebrew text in later publications. My translation attempts to more closely follow the the original Hebrew and read as contemporary and unstilted.
Our God and God of our ancestors:
Accept with mercy our prayer for our land and its government. Pour out your blessing on this land, on its President, judges, officers and officials, who work faithfully for the public good. Teach them from the laws of Your Torah, enlighten them with the rules of Your justice, so that peace, tranquillity, happiness and freedom will never depart from our land. God of all that lives, please bestow Your spirit on all the inhabitants of our land, and plant love, fellowship, peace and friendship between the different communities and faiths that dwell here. Uproot from their hearts all hate, animosity, jealousy and strife, in order to fulfil the longings of its people, who aspire for its dignity, and desire to see it as a light for all nations.
And so may it be God’s will that our land be a blessing for all who live on earth, and that fellowship and liberty will dwell between them. Establish soon the vision of your prophet: Nation will not raise a sword against nation, and they will no longer learn war (Isaiah 2:4), and, as it is said: for all of them will know Me, from the smallest to the greatest (Jeremiah 31:34). (Amen)
This translation can also be found alongside the original Hebrew, and with background information and various download formats at the Open Siddur Project.