A third party is a part that doesn’t fit the criteria of belonging to the two dominant parties of the US. In simple terms, it is any party that isn’t the two dominant parties (republican and democratic).
In ancient rome they built their roads out from rome towards the frontier of the empire as they conquered
"His Majesty's government view with favour the establishment in Palestine
of a national home for the Jewish people, and will use their best
endeavours to facilitate the achievement of this object, it being
clearly understood that nothing shall be done which may prejudice the
civil and religious rights of existing non-Jewish communities in
Palestine, or the rights and political status enjoyed by Jews in any
other country." basically, it claimed Israel was gonna be the religious sanctuary for all jews and no one can infringe on that right.