Do you support the promotion of another countries interest?
If you don't support the promotion of democracy, do you support the promotion of anything?
All real modern conservatives, I think, begin with recognition of Edmund Burke, and in particular his book REFLECTIONS ON THE REVOLUTION IN FRANCE.
Other leading conservatives, in my opinion, include but are certainly not limited to: Friedrich von Hayek, Whitaker Chambers, G.K. Chesterton, Hilaire Belloc, James Burnham, William F. Buckley, Thomas Sowell, Joseph Sobran, Milton Friedman, Winston Churchill, and, dare I say it, Ronald Reagan.
Depends on what you mean by “support” and what you mean by “interest”.
Of the people on that list I’d go with Chesterton, sowell, Buckley being my favorite conservative “philosophers”.
Which isn’t to say I agree with everything they say.