Kapil Sibal dumps Congress: Is the challenge to Gandhis over?

Announcing that he had resigned from the Congress last week, Kapil Sibal today filed his nomination for the Rajya Sabha as an independent supported by the Samajwadi Party.

So, with Kapil Sibal, who was a member of the G-23 who sought organisational reforms in Congress, resigning, is the challenge to Gandhis over?