It’s been just over five years since a hack of the Bush family emails exposed former president George W Bush as a dedicated student of painting. Since that unintended exhibition of early work – a series of self-portraits mid-toilette – the world has awaited the development of the artist’s oeuvre with bemusement, derision and incipient admiration.

A lot has happened since 2013. Time – or more likely the continued devolution of the Republican party – has transformed the once deeply unpopular leader into an adorable totem in the rearview mirror. He’s worked diligently to become a much better painter, studying under the tutelage of the young African American portraitist Sedrick Huckaby, an old Texan, Roger Winter, and the landscape artist Jim Woodson.

Last week, the first full monograph of his work was published. The volume consists of 98 portraits of US veterans with accompanying essays about them written by Bush himself. The title, a nod to John F Kennedy’s Profiles in Courage, is Portraits of Courage: A Commander in Chief’s Tribute to America’s Warriors.

To dispense with preliminaries: is Bush any good as an artist? The answer is yes. George W Bush is a talented painter with an affecting vision and immense promise. As befits a ranch man, he has a way with the brush. As befits a commander-in-chief who once called himself “the decider”, his gestures are decisive. A review of an earlier series of portraits of world leaders show an artist’s whose dexterity was outstripped by his exuberance. But even in those, the glow of an incipient vision pulsed from within. For instance, despite the dumpster-fire technique, there was a certain truthiness to the sallow side-eye meanness of Vladimir Putin that no Kremlin portraitist could ever replicate.

But in this more recent work, Bush’s skill now runs abreast with his vision. The vast majority of the paintings are tightly cropped portraits painted from photographs. Faces occupy nearly the entire canvas, against a brightly colored background that is often the underpainting left raw. These are men – and they are nearly all men – Bush either met in various military hospitals while he was president or during the mountain bike rides and golf tournaments he organizes for veterans through the military service initiative at his not-for-profit organization, the Bush Institute.

Bush’s subjects come to the former president and artist in such a way that all of them have sustained serious injuries. Their bodies were blown apart by IEDs and shrapnel. Their limbs shorn from their body and replaced with plastic and metal prosthetics. Even when the physical wounds have healed, their minds have been irreparably shaken. TBI and PTSD occur in nearly every one of the essays, which are written using formulaic but effective repetition. Each essay opens with an anecdote of how Bush first met his subject, a brief recapitulation of his or her tours of duty, the catastrophic moment of injury, a difficult recovery, even more difficult psychological readjustment, and finally how the virtues of physical activity buoyed these men from their depression. Each story differs but slightly and as a corpus they are dull – and that dullness, the flat sameness of horror retold, is perhaps one of Bush’s points.

SFC Michael R Rodriguez. Photograph: George Bush

As Bush painted, he writes, “I thought about their backgrounds, their time in the military, and the issues they dealt with as a result from combat.” Again and again, Bush pushes the paint around the canvas to form impasto swirls and jetties, mimicking the scars and disfigurements of his subjects. Their expressions are often awkward, as if caught unawares, though it isn’t clear whether this awkwardness is the result of the execution of the painting or simply the source. Regardless, Bush captures something in these men that is steely and sad and crackingly human. In the tense and wary flat affect of Staff Sgt Zachariah Collett, hit by an IED in Iraq in 2003, in the knit brow of PO3 Chris Goehner, discharged with PTSD in 2006, in the awkward regard with which Cpl David Smith stares at us (and at Bush) from our waist-level vantage point, these are raw portraits of men still at the margins.

For many, the most interesting aspect of Bush’s work isn’t on the canvas at all. In this era of post-technique conceptual art, in which Jeff Koons relies on his minions and Richard Prince reproduces Instagrams, that’s not a knock. Here it is as plainly as I see it:

As commander-in-chief, George W Bush sent thousands of American troops into a war. Many died. Many were injured. And all were in harm’s way. This bloody war, now almost 15 years old, was broadly and widely condemned as unjust and unwise. Upon becoming a civilian again, Bush became a painter and his subjects were the very men torn to shreds, quite literally, by his own policy. As an artist, Bush seems somehow to be working through what might not be a sense of guilt exactly – he’s never expressed remorse for Operation Iraqi Freedom – but is certainly a deep-seated sense of duty to his subjects. In their repetition, these portraits are obsessive and to the extent that they represent just a fraction of the nearly 4 million post-9/11 veterans, they are terrifying.

Does it matter, from a critical standpoint, that Bush might not be aware of his obsession? Certainly he would defer the interpretation laid forth above. But it’s precisely this dramatic irony that gives Portraits of Courage its numinous and haunting quality. This book isn’t just art – though it is art – it is also alive and painful and, above all, real. For who else but this artist could force us to ponder so intently how naivete functions in art and how it functions in policy? What painter but George W Bush could be party to one of the most complex relationships between artist and subject in recent memory? There is the touching narrative here, too, of a man discovering what he calls his “inner Rembrandt”. To read George W Bush name-drop Lucian Freud and Joaquin Sorolla as inspiration not in terms of subject matter but how they approached light and color is, at least for me, a really hopeful and tender thing. And it’s touched with sadness, too. After he began painting, Bush writes, “I started to see the world differently. Shadows become colors.” One can’t help but wonder: what if this man, who saw the world in black and white, had taken up the brush sooner? Perhaps he wouldn’t have had such a terrible array of injured veterans to take as subjects today.

• This article was amended on 7 March 2017 to correct the name of George W Bush’s book, from Portraits in Courage as an earlier version said. It was also amended on 20 March 2017 to correctly identify SFC Michael R Rodriguez, pictured in the portrait above.