Can Rational Team Concert and IntelliJ coexist?

Rational Team Concert's integration page says "Jazz Connect for IntelliJ IDEA enables developers using JetBrains to leverage the power of Rational Team Concert for source control, work item management, and collaboration services."

Also have a look at this page for other integrations of RTC.

This is going to be hard - you could configure IntelliJ to call the RTC scm commands, but this is not going to be that easy. I have heard of a company planning to build an integration, but not seen this myself (they might have finished this already). Company is called CM-Logic and is UK-based.

I use both of them together. You can't use IDEA to checking or deliver code, but you can certainly edit code in IDEA and then use the RTC tools to checkin.

One warning: I'm on Ubuntu 64-bit, and everything is fine. I have a co-worker using IDEA & RTC on Windows 7 and he has to close IDEA every time he wants to check-in because IDEA has file locks that RTC balks at.

I have no knowledge of the CM Logic's JazzConnect-IDEA product. There doesn't seem to be any way to download a demo of it either.

I would say that it could, it looks like IntelliJ offers an version control integration point as does the Jazz SCM component, but I am not familiar enough with IntelliJ to say for sure(looks like ClearCase is already on the list so they are adding support for vendors), I would think that without a full fledged integration where your Work Items are integrated into your development RTC starts to loose it's flair but may be not for your management :)