first, start with the government structure we (in the united states) have. it has its kinks and inefficiencies, but it basically works. then fill it with the following:
in the house of representatives, centrists. communists and fascists strictly verboten.
in the senate, leftists. i'll stop short of saying downright baby-eating marxists but part of me wants to.
in the courts (especially the supreme court), conservatives all the way. i hate the phrase 'strict constructionist' but the shoe fits.
for president, someone who is simultaneously 1. not affiliated with either party of the current two-party system, 2. ideologically libertarian, 3. economically neutral good in the i-roll-twenties etymology (which naturally eliminates any sith lords—huzzah!)., 4. socially progressive, 5. an actual scientist, and 6.
an independent and unmolested media armed with the much-hyped shield law.
and finally, for every single state and local office in the entire nation, from governor to county comptroller, this guy. (though as a condition of his holding office, he must uphold his election-season promise to frickin' blog more, yo.)
elections are instant runoff and are fewer and farther between, with single-term limits at every level.
there is, of course, always more, but this is the gist. in my head this guarantees that the government itself finds the balance between current and stable. pipe dream? oh yes, but a healthy one.