The following Bottom Lines have been updated following this week's primaries in Delaware and Massachusetts.

DELAWARE:

Democratic U.S. Sen. Tom Carper, who won this seat in 2000, got a primary challenge to his left from community activist Kerri Harris. After several Democratic House incumbents faced similar challenges, Carper ramped up his campaign to ensure his supporters went to the polls. He had no trouble defeating Harris, 65 percent to 35 percent. The Republican nominee is Sussex County Councilman Ron Arlett, who won the primary with 67 percent to 28 percent for former PayPal executive Eugene Truono and perennial candidate Rocky De La Fuente, who took 5 percent. The primary is very likely to be the most challenging part of Carper’s bid for a fourth term. The race is in the Solid Democrat column.

MASSACHUSETTS:

Republicans would like nothing better than to defeat Democratic U.S. Sen. Elizabeth Warren, who won this seat in 2012 by defeating GOP U.S. Sen. Scott Brown, 54 percent to 46 percent. But, Brown’s victory in a 2010 special election was something of an outlier in

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