So that's the challenge, keep the war going [or in a stop-start pattern] for 13 or more years.
Lesser challenge: Keep the Bosnia war [lasted 92-95 in OTL] going as long as the Syrian Civil War. [5 years & 8 months]
Alternate challenges:
Make post-2003 Iraqi sectarian strife end its violent phase or the Syrian civil war end its violent phase in under 4 years.
Lesser challenge: Keep the Bosnia war [lasted 92-95 in OTL] going as long as the Syrian Civil War. [5 years & 8 months]
Alternate challenges:
Make post-2003 Iraqi sectarian strife end its violent phase or the Syrian civil war end its violent phase in under 4 years.