Believe it or not, Syria doesn't base their defence policy around the USA alone. 

The Mig 25 and Mig 31 are probably the best fast jets to come out of the USSR, and the type has shown itself to be hugely successful as a fast recce platform, over the Middle East in particular.  Remember when Arab Mig 25's acted with impunity over Israel because their F4's couldn't intercept them?

Correct, that's why I said I figure it's a move aimed at Israel, not us.  However, these aren't reconnaissance jets, they're interceptors.  Furthermore, Israel would splash them within seconds of crossing into Israeli territory anyway.  If they have any usefulness at all to the Syrians, I'd guess it's mainly the other way around:  The Syrians are looking for some way to hold Israeli ISR aircraft at risk.  Also, by all accounts, Assad is really torqued off by the ability of Israeli aircraft to perform supersonic passes untouched by Syrian defenses over his home in Latakia, and he's probably willing to try just about anything/everything to find some way to counter them.

 

This will be the first export sale of both the MiG-31 and the MiG-29M.  If the rumored PANTsIR deal works out, too, along with the other recent arms buys, this is starting to actually become a significant modernization effort overall.  In doing all this they owe a huge favor to Iran who appears to be fronting a major portion of the cash to pay for it all.

 

Hopefully the Lebanese will make good on their reported threat of releasing evidence of Syrian culpability in arming the terrorists in the recent fighting against the Lebanese Army.  Unfortunately, I'm sure it wouldn't matter as I doubt we'd actually act on it anyway.  Why change now?

Also, by all accounts, Assad is really torqued off by the ability of Israeli aircraft to perform supersonic passes untouched by Syrian defenses over his home in Latakia, and he's probably willing to try just about anything/everything to find some way to counter them.

Try try again until u succeed. And the Taleban and Hezbullah have shown that USA USSR & Israel CAN be beaten. Blame the politicians on our side for showing weakness. Anyways the Russian systems are quite a bit better now -considering Chinese electronics will help a lot too. What Russia lacked was quality manufacturing and electronics--both have been reasonably corrected. if u look at the latest Mi-29K built for INdia the quality is great-check the welds.

Rosobonexport official at the Le Bourget air show now denies such a deal is in the works.
There's no smoke without a fire...

True, they have.  They quickly cam out in denial of the rumored PANTsIR sale, too.  I've also read that one or more Russian government officials privately have confirmed the MiG deal.  Apparently it's quite the buzz around Le Bourget right now.  Perhaps it's all one big rumor after all.  I think we'll find out pretty soon one way or the other.

What do big, expensive Russian fighter jets - technological elements wedded to 3rd generation warfighting - have to do with a 4th generation fight?

Especially since neither the Taliban nor the Hizballah have beaten America.