Logan: Iran has been "ready" for talks before

President Mahmoud Ahmadinejad's declaration that Iran is now ready to engage in nuclear talks with the West is probably both an acknowledgment that sanctions against his country are having an effect, and another effort to try and delay harsher measures from the international community.

CBS News chief foreign affairs correspondent Lara Logan tells "CBS This Morning" that, while the battery of economic sanctions is making life difficult for Iran -- shrinking its national economy by a whopping 50 percent in just a matter of months -- the Iranians are masters at this game.

They do this over and over - give their allies just enough to be able to continue resisting the call from the U.S. and other countries for more comprehensive sanctions.

China buys a huge amount of oil from Iran, making it a reticent United Nations Security Council member when it comes to harsher sanctions, and Russia is keen to try and maintain the status quo balance of power in the region, and has thus also resisted the call.

Because the effectiveness of sanctions depend on how many countries choose to enforce them, many see the time approaching when the U.S. - or Israel - may decide sanctions and covert operations are insufficient to prevent Iran obtaining a nuclear weapon.

To see Lara Logan's full analysis of the standoff with Iran, click on the video player above.