US President Joe Biden has been defended by a former Democrat strategist, as concerns grow for the US leader’s cognitive ability ahead of the November election. In recent months, Biden has been forced to defend himself against the critics after suffering a string of blunders during public speaking engagements. Biden has told reporters his “mind is fine” as calls grow for the Democrats to find a replacement for the leader. As he faces a re-election against Republican candidate Donald Trump, reports suggest former First Lady Michelle Obama could be a top choice candidate for the party. In a disc…