The address is not an official State of the Union because a president’s first speech before Congress is not considered a State of the Union. Source

Republican front-runners Donald Trump and Ted Cruz are fighting for votes ahead of next week’s South Carolina primary. In a new ad, Ted Cruz attacks Donald Trump’s conservatism on the topic of abortion. With more on the fight within the GOP field, Matt Mackowiak from Potomac Strategy Group and CBS News’ Steve Chaggaris join CBSN. Source

It’s music’s biggest night at the 58th Grammys Awards show in Los Angeles, and there is chatter that there will be plenty of political statements made through special performances. With more on what to expect tonight, CBS News’ Anthony Mason joins CBSN from the Staples Center. You can watch the Grammys on CBS tonight at 8pm ET. Source

After the sudden death of Supreme Court Justice Antonin Scalia on Saturday, there’s been a growing fight over his replacement. President Barack Obama needs the Senate’s approval to elect a nominee on the Supreme Court. His choice could shift the conservative balance in the court; however, many Republicans vow to block Obama’s pick, no matter who that may be. With more, CBS News’ Jan Crawford joins CBSN. Source

An investigative piece in the New Yorker magazine investigates how TMZ gets the scoop on breaking stories of celebrities. In 2006, the entertainment news website exposed Mel Gibson’s anti-Semitic comments. In 2009, TMZ broke the news of Michael Jackson’s death. The site also posted video of Baltimore Ravens’ running back Ray Rice hitting his fiancé, and another of Beyonce’s sister, Solange, attacking Jay Z in an elevator. Writer Nicholas Schmidle joins “CBS This Morning” to discuss his article, “The Digital Dirt: How TMZ Gets the Videos and Photos that Celebrities Want to Hide.” Source

Xs and Os are the marks of a truly heart-felt love letter. And keeping the love letter alive is the goal of a play with a uniquely qualified cast. Serena Altschul sits down with Ali MacGraw and Ryan O’Neal, the “Love Story” costars now appearing on stage in “Love Letters.” Source

Ted Cruz called out Marco Rubio for his past stances on immigration and Rubio responded in a biting fashion at Saturday’s GOP debate. Source

In part two of Saturday’s GOP debate, the candidates talked about their plans for health care and how to handle social security. Source

Donald Trump and Jeb Bush spar over how to approach the fight against ISIS and the Assad regime in Syria. Source

The Republican debate takes a dramatic turn as Donald Trump and Jeb Bush clash over former President George W. Bush’s record on national security. Source