Six House Republicans who are running for Senate this year in competitive states voted for the House GOP's 2015 budget -- and Democrats wasted no time in making it a top campaign issue. 

Reps. Bill Cassidy (La.), Shelley Moore CapitoShelley Moore CapitoLawmakers try again on miners’ pension bill How the effort to replace ObamaCare failed It's time to eliminate the secretive Pharmacy Benefit Manager pricing practices MORE (W.Va.), Tom CottonTom CottonHouse bill set to reignite debate on warrantless surveillance Republicans jockey for position on immigration The Hill's 12:30 Report MORE (Ark.), Steve Daines (Mont.), Cory GardnerCory Scott GardnerRepublicans jockey for position on immigration Bipartisan bill would toughen North Korea sanctions, require Trump's strategy GOP senators push for delay of ObamaCare insurer tax MORE (Colo.) and James Lankford (Okla.) all supported Rep. Paul RyanPaul RyanThe Hill Interview: Budget Chair Black sticks around for now Gun proposal picks up GOP support GOP lawmaker Tim Murphy to retire at end of term MORE's (R-Wis.) budget. 

Previewing campaign advertisements to come, the Democratic Senatorial Campaign Committee said GOP Senate candidates "overwhelmingly" voted for the GOP budget that would cut spending by $5.1 trillion over the next decade with overhauls of social programs.

"Republican Senate candidates are sending a message loud and clear to women of their states that if elected to the Senate, they will put special interests like Koch brothers first, not women and middle class families," said DSCC spokeswoman Regan Page.  

Sen. Mark PryorMark PryorMedicaid rollback looms for GOP senators in 2020 Cotton pitches anti-Democrat message to SC delegation Ex-Sen. Kay Hagan joins lobby firm MORE's (D-Ark.) campaign, a top GOP target, criticized the proposal in the budget to create an optional private system for future seniors.

"Congressman Cotton just isn't listening to Arkansas seniors, and that's why he continues to vote for these irresponsible plans to end Medicare as we know it," said Erik Dorey, a Pryor campaign spokesman.

In a statement, Cotton said the GOP budget "preserves Medicare for future generations."

"I urge my colleagues in the Senate to stop sitting idly by and waiting for our country to descend into financial ruin," Cotton said.

Newly-appointed Sen. John Walsh (D-Mont.) hit his opponent with "10 Ways the Daines Budget hurts Montanans." 

“With a single vote, Congressman Daines has put thousands of Montana seniors, children, veterans and families at risk while protecting his fellow millionaires and big corporations,” said Walsh spokeswoman Lauren Passalacqua. “Montanans deserve an explanation from their congressman about his choice to protect his friends at the expense of the people he is supposed to serve.”

But in the Georgia primary, GOP members didn't think Ryan's proposal went far enough. The three House Republicans -- Reps. Paul BrounPaul BrounCalifornia lawmaker's chief of staff resigns after indictment Republican candidates run against ghost of John Boehner The Trail 2016: Let’s have another debate! MORE, Phil GingreyPhil GingreyBeating the drum on healthcare Former GOP chairman joins K Street Former Rep. Gingrey lands on K Street MORE and Jack Kingston -- who are running for Senate all voted against the budget. The three also voted against the December budget deal negotiated by House Budget Committee Chairman Paul Ryan (R-Wis.) and his Senate counterpart, Patty MurrayPatricia (Patty) Lynn MurrayChildren’s health-care bill faces new obstacles Overnight Health Care: Schumer calls for tying ObamaCare fix to children's health insurance | Puerto Rico's water woes worsen | Dems plead for nursing home residents' right to sue Schumer calls for attaching ObamaCare fix to children's health insurance MORE (D-Wash.).