Probably. As far as anybody knows, the FBI and NSA are on the same level of cryptography technology as the rest of the world is. AES and SHA-1 are currently the national standards for encryption and secure hashing. AES is what TrueCrypt uses (as do most SSL connections and WPA/WPA2 connections).

There are some things to keep in mind though:

Fine print: As others have pointed out elsewhere in the thread, it's possible to extract encryption keys from RAM even if the computer has been (very... within several minutes) recently shut down.

More fine print: Pick a weak passphrase, and you may be shit-outta-luck. Also, brute forcing for passphrases up to a certain complexity is viable.

Tin foil hat: A conspiracy theorist may assert that the feds are far ahead of academia when it comes to cryptography, as was likely the case several decades ago (see the history of DES). I'm not sure that I believe that, because cryptography has a huge place in academia now, worldwide. It's possible, but I doubt they've broken AES.