Resnick, Mike. "Over There"
Divergence: 1917 CE
What if: Under duress, Woodrow Wilson in May 1917 gave Teddy Roosevelt permission to re-form the Rough Riders and go to France.
Summary: TR discovers that the natures of war and the enemy have changed in 20 years.
Published: In Isaac Asimov's Science Fiction Magazine, April 1991; What Might Have Been? Volume 3: Alternate Wars (eds. Gregory Benford and Martin H. Greenberg), q.v.; Will the Last Person to Leave the Planet Please Shut Off the Sun?, Tor 1992 (0312852762BUY), Tor/Orb 1994 (0312890109BUY); The Way It Wasn't: Great Science Fiction Stories of Alternate History (ed. Martin H. Greenberg), q.v.; Roads Not Taken: Tales of Alternate History (eds. Gardner Dozois and Stanley Schmidt), q.v.; We Could Do Worse (audiobook, ed. Martin H. Greenberg), q.v. Asimov's Science Fiction Magazine: 30th Anniversary Anthology (ed. Sheila Williams), Tachyon 2007 (1892391473BUY); and The Other Teddy Roosevelts, q.v.