CARSON CITY, Nev.-- Nevada Rep. Jacky Rosen launched her campaign for U.S. Senate on Thursday with significant support from fellow Democrats, becoming the first major challenger to enter the 2018 race for Republican Sen. Dean Heller's seat.

Democrats believe Heller is the most vulnerable Senate Republican up for re-election in 2018. Rosen's official campaign announcement called him an "enabler" of President Donald Trump.

Heller said last month that he opposes a GOP plan to overhaul federal health laws, but Democrats blast his previous support in rolling back former President Barack Obama's landmark health law.

Rosen and every other Democrat in Congress have opposed the GOP plan.

Rosen's announcement was closely followed by endorsements from the Democratic Senatorial Campaign Committee and Nevada's two other freshman Democratic congressional members, Sen. Catherine Cortez Masto and Rep. Ruben Kihuen.

The quick show of support for Rosen sent a clear and public message as Democratic Rep. Dina Titus considers entering the race.

"It's a personal and political decision," Titus said in a statement Thursday. "The election is 16 months away and I am evaluating in what role I can continue to best serve the citizens of Nevada."

Titus, whose district includes the Las Vegas Strip, was first elected to Congress in 2008. Heller was elected to the House in 2006 and appointed to the Senate in 2011.

Rosen was a computer programmer and synagogue president until winning her House seat in 2016.

She embraced her role as political outsider in a statement and phone interview Thursday.

Around the time "Obamacare" was wending through Congress, Rosen was taking time off work to care for her ailing mother, father, mother-in-law and father-in-law who all at once were coping with broken bones, cancer and dementia.

"I might not have been in Congress but I lived it on the front lines with the people that I loved the most," Rosen said. She later added, "That's my experience with health care -- being a part of this community and a part of a family, and that tells me everything I need to know because health is personal and we need to protect it."

Republicans argued Rosen's support from former Sen. Harry Reid, who picked her for the 2016 race, contradicts her position as a political outsider. "Thought Nevada was free of Harry Reid?" Heller spokesman Tommy Ferraro said. "Think again."

National Republican Senatorial Committee spokesman Michael McAdams said, "Nevadans looking for an independent voice will be disappointed to find Jacky Rosen is nothing more than a pawn for Harry Reid, Nancy Pelosi, and radical liberals."

Rosen plans to campaign in the Las Vegas area this weekend and tour the state during the August congressional recess.