Chinese Weapons to Iraqi Insurgents?

The following link is to a piece in the current issue of the Weekly Standard. It's written by John Tkacik, a former foreign service officer in China who's now at the Heritage Foundation, the conservative think tank in D.C. This piece is a little thinly sourced--much seems to come from a single White House source--but its thesis is a familiar (if explosive) one in certain DC circles: to wit, the Chinese are equipping Iraqi insurgents (via Iran) with (mostly) small arms (sniper rifles etc.) According to Takcik, moreover,they are doing so intentionally--in order to keep the US bogged down in Iraq so it effectively ignores everything else. This presumably allows China a free hand to do whatever it wants anywhere else.
But that's my problem with this thesis. What, exactly, would both the US and China be doing differently if the US wasn't bogged down in Iraq? Would Washington have more leverage over Beijing on, say, the Iranian nuclear issue (where Beijing's a key player on the Security Council), or on Darfur? I'm not sure I see it. Anyway, this piece, though controversial, is worth reading.
http://www.weeklystandard.com/Content/Public/Articles/000/000/013/956wspet.asp