It is worth recalling Rahul Gandhi's promise after the December 2013 Delhi elections - which saw Mr Kejriwal's Aam Aadmi Party (AAP) pull off a stunning debut. The Congress had emerged as a poor third (but with a quarter of the total vote). Mr Gandhi said he had got the voter's message loud and clear, and that he would respond with change that was "beyond your imagination". Fifteen months later, it will take some pretty wild imagination to spot any change in the party - other than the slide into irrelevance. Despite repeated hammering in the Lok Sabha and five subsequent state Assembly elections, not to mention four Assembly elections that preceded the parliamentary election, there is the same old kowtowing to the ruling family, the same old courtiers conveying the wishes of the "high command", the same long absences by the prince of the court, then his sudden appearance as an angry man in beard at a public rally, then disappearance again.
A year ago, Mr Kejriwal was in a bigger mess than Mr Gandhi. He had thrown away a mandate, angered voters, and then eaten humble pie in the Lok Sabha elections. Since then, Mr Gandhi has played hide and seek while Mr Kejriwal has rebuilt his reputation and his party, in the very city where Mr Gandhi lives. While one has delivered resolute reconstruction, the other has been missing in action. There is no further proof required that Mr Gandhi has no taste for the job of rebuilding his party, and no stomach for a political fight. The best thing he can do for the Congress is to get out of the way.
The Congress could hope to retain its political corner so long as its principal opponent was the BJP. It could appeal to poor voters with its populism and left-of-centre stance, and retain some of its minority support base. But the AAP has barged into that corner, and at the same time appealed to both the middle class and the business community (especially small traders). The AAP has also brought into the fray young, fresh faces and enthusiastic cadres; it has articulate spokespersons from social backgrounds that in another age would have been apolitical; and it has shown how to use the "social" media as well as the radio. Its promises still seem over the top, but on every front it has shown up the Congress as a spent force devoid of imagination, ideas and energy. In short, the existential challenge for the Congress comes not from the BJP but from the AAP. Or, even more correctly, from the nature of its non-leadership.