A 'politically calculated silence'?
So why has this outspoken defender of human rights seemingly lost her voice?
It is, says Mathieson, "a politically calculated silence" that reflects the re-entry of Suu Kyi and her National League for Democracy into the political fold in earnest.
The former political prisoner, who described herself to CNN last year as having "been a politician all along," has repeatedly said she wants to be the next president of Myanmar. The 2015 general election will see her compete against the military-backed party of President Thein Sein on one flank, and hardline anti-regime activists on the other.
"She's playing a different game now," said Mathieson. "People still see her as this great Nobel Peace Prize-winning icon for human rights and democracy -- what they don't get now is she wants to be a politician taking on one of the most brutal militaries in the world."
Mathieson said Suu Kyi's political fortunes depended on negotiating several challenges, including trying to strike a balance between international expectations -- "most of which are outlandishly unfair and ill-informed" -- and a "very complicated domestic setting where if she suddenly did do a volte-face and spoke out on behalf of Muslims, it would be politically disastrous."
Moreover, she was operating in a complicated post-authoritarian domestic environment in which she had opted to work inside the system as a lawmaker and was compelled to keep senior military figures, who still hold a strong grip on the reins of power, onside. "I can understand why she's walking on eggshells," he said.