Biden is Trump's most anticipated -- and feared -- rival [View all]

[WeekiWater]

Washington(CNN) He's the Democratic candidate President Donald Trump has long worried would emerge as his general election rival. Now, with the entry of former Vice President Joe Biden into a crowded primary field, a race that once seemed to Trump like abstract chatter has sharpened into a concrete proving ground that will challenge his hold on the nation's political spotlight.

Already, Trump has noticed with unpleasant surprise that the Democratic field is occupying more and more airtime and print inches -- space he has enjoyed largely to himself for the past two years. He's worked to counter the tide, returning to his practice of conducting phone interviews with friendly television hosts and increasing his angry output on Twitter.

CNN