"ideological source" is an acceptable phrasing in written English, and it can be used to refer to the source of an idea or belief.
For example, "The author draws on an ideological source for the beliefs outlined in the essay."
Both sides were purportedly supported by the Bulgarians, who sought to promote instability, regardless of its ideological source, in a nation allied with the United States.
Now the case for Brexit is coming from quite a different ideological source: the hard left has reservations about the EU as a trading body, for sure, but almost nobody thinks we will be better protected against the corporate capture of social resources by TTIP (Transatlantic Trade and Investment Partnership) and what follows if we are outside Europe, with Cameron or worse in charge.
Then there is the accusation that, as the supposed ultra-conservative "Wahhabi Central", Saudi Arabia is the ideological source of the IS demon seed.
Some also credit Tzara with having provided an ideological source for the development of rock music, including punk rock, punk subculture and post-punk.
That makes the ideological sources, like the blogs, more vulnerable".
Usually, though, they take their cues from ideological sources.
It's amazing what you can do, even with ideological sources.
Mr. Newhouse's account of the political and ideological sources of these strategic missteps is less compelling than his critique of American policy.
His government issued a statement saying "success over terrorism does not come with fighting in Afghan villages, but by targeting its sanctuaries and financial and ideological sources across the borders" — a view he said was borne out by the leak of the military documents.
NGOs that are de facto but not explicitly anti-Israel such as Human Rights Watch and Amnesty International (which, for example both tend to hire employees for their Mideast divisions that have backgrounds in anti-Israel activism), aren't covered by any such ban/discouragement of using "ideological sources"–only the one Israeli organization that serves as a watchdog on such groups is banned.
In the context of the debate about the ideological sources of the American Founding the term "civic humanism" serves to separate strands of republican thought; it distinguishes a philosophic temper and language and not a party political alignment such as Jeffersonian Republicanism.
