The best book ever written by a Minnesotan — one of the six most important American novels, poet Carl Sandburg said — is a tragedy of immigrant life.

Ole Edvart Rolvaag, whose son Karl would one day become Minnesota's governor, emigrated from Helgeland, Norway, to the Upper Midwest in 1896. Instantly, he succumbed, he wrote, to "a feeling of utter helplessness, as if life had betrayed me … the sense of being lost in an alien culture. The sense of being thrust somewhere outside the charmed circle of life."

I last wrote about Rolvaag's heartbreaking 1926 masterwork, "Giants in the Earth," almost 30 years ago. It was in an editor's note for another publication that at the time was reporting on maladjustments among Minnesota's Hmong refugees, who were then fairly recently arrived.

This spring seems another suitable moment to remember Rolvaag and his book, as Minnesotans struggle to comprehend, or even imagine, the kind of alienation that is inspiring young Somali-American men in our community to sign up for duty with savage terrorist armies in the blood-drenched Middle East.

Rolvaag's harrowing account of the sufferings of my Norwegian immigrant forebears in the 19th century at least makes one thing clear: Self-destructive estrangement among new arrivals to America is nothing the least bit new.

"If you couldn't conquer that feeling," Rolvaag continued, describing the Scandinavian immigrants' anguish, "if you couldn't break through that magic hedge of thorns, you were lost indeed.

"Many couldn't and didn't — and many were lost thereby."

We like to say America is a nation of immigrants. But our understanding of immigrants' psychological struggle — that "sense of being lost in an alien culture" — seems to die with the first generation or two.

Again and again, down through the years and amid various waves of immigration, well-settled Americans have been shocked and scandalized by the difficulties and failure to adjust of each new immigrant group — Irish, Italians, Germans, Jews, Japanese and all the rest.

The terror recruitment crisis among our Somali neighbors is serious and dangerous; our response must be dry-eyed and unsentimental. The law enforcement role is vital.

But the ultimate, unavoidable challenge is to help these relatively new arrivals break through their own "hedge of thorns" and find a more comfortable place in American life.

It could only aid that effort if established Americans (and, maybe most important, Somali-Americans themselves) would recognize that immigrant alienation and confusion are, ironically but truly, distinctively American experiences — pains nearly all Americans' immigrant ancestors suffered.

We in later generations have forgotten, but that's to our discredit.

For example, an obsessive longing to return to one's homeland, no matter what it takes, was something Rolvaag — writing his great American novel in Norwegian, not English — vividly described among certain Norwegian settlers on America's virgin prairies:

"She sat perfectly quiet, thinking of the long, oh, so interminably long march that they would have to make, back to the place where human beings dwelt.

"It would be a small hardship for her, of course, sitting in the wagon; but she pitied Per Hansa and the boys — and then the poor oxen …

"[But] he certainly would soon find out for himself that a home for men and women and children could never be established in this wilderness."

One unsettling difference today, of course, is that the dream of going "home" can now become not merely a destructive fantasy but a nightmare reality. Terror groups are all too eager to make it come true. And to do so they prey not just on immigrant vulnerabilities but on another set of distinctive yearnings, in another population that is eternally restless and uncomfortable. That is, young males.

Across all times and cultures, young males are drawn irresistibly to the opportunity to go adventuring in one way or another, to confront danger and struggle, and ideally to do it in the company of other young males — as part of what Shakespeare called a "band of brothers" committed to a cause.

ISIL and Al-Shabab are nothing if not dark but vivid expressions of this deep masculine need.

A tough question is whether modern American culture, with its complicated and ambiguous gender roles, can satisfy this need nearly as well for this population.

Fact is, there can be no guarantee that America, even over time, will be able to assimilate every new immigrant group as effectively as it has become home to so many once-troubled groups in the past. Yet we owe it to our forebears not to underestimate how unlikely their success, too, once looked.

It has fallen to comparatively few souls in human history to suffer the torments of the immigrant — the wrenching exile from all that one belongs to, from all that feels proper and civilized, from Rolvaag's "charmed circle of life." Yet nearly every American is an American because someone in the past endured that ordeal.

Call me an optimist, but I we think we Norwegian-Americans are making progress in adapting to American life. Our newer citizens deserve understanding and tough-minded support as they strive to do the same.

Anything less would be unworthy of those who went before us, and who, as Rolvaag put it, "toiled and suffered and died that their children might inherit the promise."

D.J. Tice is at Doug.Tice@startribune.com