He’s the Democratic candidate President Donald Trump has long worriedwould 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. https://www.cnn.com/2019/04/25/politics/donald-trump-joe-biden-rivals/index.html
