Battle for the Senate: Six races to watch in 2018

Texas: Cruz vs. O'Rourke

Sen. Ted Cruz is facing a tough battle for a second term against Beto O’Rourke, an upstart Democrat representative who has gained national media attention for his progressive platform and cross-Texas campaign trips. O'Rourke made a name for himself by rejecting direct funding from political action committees and in-house pollsters -- two hallmarks of the modern campaign -- while hauling in $70 million in individual donations. Cruz has responded by doubling down on his conservatism, embracing the Trump platform and rallying alongside the president in recent days.

RealClearPolitics Rating: Leans Republican

Missouri: McCaskill vs. Hawley

Two-term Democrat Sen. Claire McCaskill is running against Josh Hawley, the state’s Republican attorney general, in one of the tightest Senate races in the nation. McCaskill, a moderate who has expressed little fear of going against her national party, is navigating treacherous territory as a Democrat in a state that Trump won by nearly 20 points in 2016. McCaskill has supported more Trump administration moves in the Senate than most other Democrats, though she voted against both of his Supreme Court nominees. On the other hand, Hawley has painted himself as a fierce Trump loyalist, supporting tariffs and the practice of family separation for those who enter the United States illegally.

RealClearPolitics Rating: Toss Up 

Tennessee: Blackburn vs. Bredesen

Former Gov.Phil Bredesen, a moderate Democrat, and Rep. Marsha Blackburn, a far-right Republican, are contesting retiring Sen. Bob Corker's open seat. Bredesen’s unusual electoral strategy showcases his conservative bona fides: He openly supported Justice Kavanaugh’s nomination, and touts the "A" rating he received from the National Rifle Association while governor. Blackburn, on the other hand, has sought to ally herself with the president to take advantage of the very partisan polarization Bredesen tends to avoid.She invokes Hillary Clinton in her speeches and has anchored her campaign to Trump's anti-immigrant message.

RealClearPolitics Rating: Toss Up

Florida: Nelson vs. Scott 

Democratic Sen. Bill Nelson’s reelection campaign pits the Florida congressional delegation lifer against Gov. Rick Scott, a Republican. The race may hinge on several issues with local and national relevance -- immigration and gun rights. It's also complicated by Florida’s complex regionalism. Support from the Trump campaign machine has helped galvanize GOP stalwarts, but the Senate race may be most closely tied to the contentious gubernatorial election between Rep. Ron DeSantis, a Republican, and Tallahassee Mayor Andrew Gillum, a Democrat. Gillum’s campaign has energized a young and diverse voter coalition, one which often fails to turn out in large numbers. Scott and Nelson's bids may end up riding the coattails the gubernatorial ticket.

RealClearPolitics Rating: Toss Up 

North Dakota: Heitkamp vs. Cramer

Incumbent Sen. Heidi Heitkamp is another Democrat seeking reelection in a state that traditionally favors Republicans. Since her consecutive “no” votes on the GOP tax bill and Kavanaugh nomination, Heitkamp has been considered the underdog in this race. Heitkamp’s vote against Kavanaugh produced her single biggest day of fundraising but also bolstered the rapid ascent of her opponent, Republican Rep. Kevin Cramer, in the polls. Now, Heitkamp’s campaign is walking a tightrope between appealing to progressive voters in the state’s eastern cities without neglecting the conservative-leaning sections of the electorate.Meanwhile, Cramer, who has made incendiary remarks ranging from dismissals of the #MeToo movement to verbal attacks toward Native American counselors with little impact on his polling, has largely parroted President Trump’s platform and has turned the election into a referendum on his presidency.

RealClearPolitics Rating: Likely Republican

Indiana: Donnelly vs. Braun

Sen. Joe Donnelly, a Democrat, has rejected party labels in his reelection bid against Republican businessman Mike Braun. This rhetoric has defined his reelection campaign as a Democrat in another state that President Trumpwon by double digits in 2016. As such, Donnelly has distanced himself from the more progressive voices in his party and embraced some of President Trump’s policies, including changing birthright citizenship, building a border wall with Mexico and voting to confirm Supreme Court nominee Neil Gorsuch. Donnelly did, however, vote against Kavanaugh. Braun, on the other hand, said he would have voted to confirm both Supreme Court nominees. He supports repealing and replacing the Affordable Care Act, preventing federal dollars from funding abortion procedures and demanding that businesses verify their workers’ immigration status.

RealClearPolitics Rating: Toss Up