The resignation of Amit Shah and Smriti Irani from the Rajya Sabha on different dates could be an attempt to stagger polls to the two seats in the upper house to ensure the BJP's victory, the Congress alleged today. Amit Shah's Rajya Sabha seat was declared vacant on May 28 after he won his first Lok Sabha election from Gandhinagar in Gujarat in last month's election. Smriti Irani's seat was declared vacant a day later; she defeated Congress president Rahul Gandhi in his constituency Amethi in Uttar Pradesh.