Washington, Oct. 23 -- President Donald Trump's plan to reverse America's involvement in "endless wars" has run up against a difficult truth: When it comes to national security, rarely can a simple solution solve a complex problem.

After abruptly announcing last week that he would "bring our soldiers home" from Syria, Trump recalibrated, and his administration said it would instead redeploy more than 700 to western Iraq to help counter the Islamic State group.

And now his latest plan faces another wrinkle: The Iraqi military said Tuesday those U.S. troops don't have permission to stay in Iraq.

Meanwhile, Turkey and Russia announced Tuesday that they would jointly patrol most of the northeastern Syrian border with Turkey, underscoring t...