“Men of ideas vanish when freedom vanishes.”

But even folks w/ bad ideas none the less have ideas, and often flurish when freedom vanishes (evidence King George's effects upon us).

The concept here is that common sense, ethics, morality, spirituality, wisdom, the expanse of brilliance, etc. go underground, being no longer available to the general public when society as a whole accepts and/or promotes the dissipation of true liberty. The current executive, legislative, and judicial patrons exacerbating victimless crimes, compelled compliance, license, etc. are all examples of the quotes implementation.

Today’s liberal/conservative, religion prejudiced, book burning, anti-individual freeman collectivists, are also examples of the quotes application

I suppose it depends on the kinds of ideas, but I understand Sandburg's intended menaing.

Yes, I believe Mike is correct in his interpretation - men of conviction and ideas do not cease to exist but they must work in less conspicuous ways. I have witnessed even greater exercise of creative voice in cultures that have repressive governments than in ones that profess unlimited free speech. The need to speak out against powerfully sanctioned evil is much stronger in those for whom it is a matter of life or death, and even mor importantly they are not ambiguous about the messages they relay.