Republican Karin Housley harshly attacked Democratic U.S. Sen. Tina Smith Friday night as she nailed down the GOP's backing to run against her this fall, while Smith won her party's support in Rochester as she trained criticism at President Donald Trump instead.

At dueling political conventions the same weekend, Minnesota Republicans and DFLers gathered to endorse candidates for what promises to be the most significant election cycle in the state in decades. The main business Friday night was endorsing candidates in two Senate races: a special election to fill the seat left open by the resignation of former Democratic Sen. Al Franken, currently held by Smith, and the seat that DFL Sen. Amy Klobuchar is seeking to hold for a third term.

Klobuchar easily won endorsement, as did her Republican opponent, state Rep. Jim Newberger. Smith won the DFL endorsement against three opponents on the first ballot, with support from 75 percent of delegates. Housley, a state senator from the Stillwater area, also won her endorsement with 75 percent of the vote.

In her speech to delegates, Housley signaled an aggressive campaign style with a slashing attack against Smith. She blasted her for obstructing initiatives sought by Trump, for her service in the administration of DFL Gov. Mark Dayton, and for her views on immigration.

"She puts the well-being of illegal immigrants above the American people," Housley said in her speech.

Smith did not mention Housley in her speech, instead aiming at Trump even as she vowed to take on drug companies that are overcharging people, increase mental health services in schools, protect immigrants and fight for net neutrality.

"I am not afraid to stand up to Donald Trump when he and his administration hurt our country," said Smith, a former lieutenant governor and DFL operative. Noting her time as a vice president for Planned Parenthood Minnesota, North Dakota, South Dakota, Smith mentioned Trump's recent move to cut off federal Title X family planning funding from organizations that perform or provide referrals for abortion.

"If Trump wants to roll back its funding and block women from the help they need, he'll have to get through me first," Smith said.

Smith faces a DFL primary opponent this August in Richard Painter, a former White House ethics lawyer in the George W. Bush administration and an outspoken critic of Trump. He finished a distant second for the endorsement, following a convention speech that saw him go after Trump for what he called "illegal and unconstitutional acts." He said his "top priority as a senator will be investigating the bribery and other high crimes and misdemeanors that have taken place in this administration."

Union member Ali Ali and attorney Nick Leonard also sought the DFL endorsement for the Senate seat. Newberger won over GOP challenger Robert Barnheiser; Housley beat Forest Hyatt and Bob Anderson, who may challenge her in the August primary.

While Smith spent a good part of her speech recounting her career in public service, Housley signaled that she would try to turn that to Smith's disadvantage.

"She's been in the background in politics for the past 12 years, and before that it was Planned Parenthood. She's a political insider," Housley said in an interview. After her stint at Planned Parenthood, Smith served as chief of staff to Minneapolis Mayor R.T. Rybak and then Gov. Mark Dayton, who elevated her to lieutenant governor in 2014.

Housley touted her experience running a small real estate business and exposing abuses in senior living facilities as a legislator.

The two parties began their weekend conventions, which are like political family reunions of sorts, replete with the occasional American flag costume, hot dogs, boisterous music, roaring speeches and plenty of infighting.

But party activists at both conventions are also anxiously focused on an election season expected to be intense, with the two U.S. Senate contests and an open governor's race; four highly competitive congressional races that could decide control of the U.S. House; plus races for all 134 seats in the state House and a state Senate special election that will determine which party controls that chamber.

Republicans in Duluth were excited about the possibility of a sweeping election that would follow their strong showing in 2016, when Trump nearly became the first Republican to win Minnesota since 1972 and the GOP took full control of the Legislature.

"Donald needs help draining the swamp," said Jim Lunde, a delegate from Lindstrom.

But hundreds of no-shows and persistent problems with electronic voting technology in the opening hours of the Duluth convention left delegates milling about and preparing for a long night. Boxes of ballots finally arrived after 7:30 p.m.

"I think the Democrats organized this convention for us," quipped Lunde.

The GOP convention featured a dance cam and a kissing cam, a welcome distraction for delegates waiting to vote.

Newberger, a paramedic from Becker, won GOP backing to take on the heavily favored Klobuchar. In an introductory video, he accused her of "working with people like Al Franken and Tina Smith to destroy America."

Newberger touted his three terms in the Legislature, during which he said he fought state agencies on behalf of constituents. "The 12-year reign of ultraliberal Amy Klobuchar must come to an end," he said.

In Rochester, Klobuchar quickly secured her party's endorsement.

"Right now, it's pretty much a nonstop shoutfest on TV," Klobuchar told the DFL crowd. "But instead of fighting about what's left and what's right, what we really ought to be talking about is the difference between what's right and what's wrong. … When we try to do right by people, DFLers, we get results."

She said she wants to bring down the costs of college and airfare, and she wants to take on pharmaceutical companies. She called for the passage of a bipartisan bill aimed at reducing the price of prescription drug prices for seniors enrolled in Medicare.

Klobuchar buttons were a common sight at the DFL convention, where there was a sea of stickers, T-shirts and pins for various candidates and causes. Delegate Diana Tunheim was wearing a Klobuchar button. She lives in Cottage Grove but has a farm in northwestern Minnesota, and she said the senator is adept at representing both the Twin Cities area and rural parts of the state.

"She understands the problems of the rural area," Tunheim said, including declining populations and stagnant crop prices.

Delegate Roger Lynn, of Crosslake, and his friend Chris Smith, of Pequot Lakes, disagreed over which DFL candidate should face Housley.

"We don't have much ethics in government right now," said Smith, a Painter supporter. "Richard Painter is just very intelligent and ethical."

Lynn said he would like to see a woman continue to hold the seat and said he likes Smith's progressive record. "She's a detailed person. She does her homework," he said. Smith and Painter will face off for the DFL nomination in the Aug. 14 primary.

Among the volunteers outside the Mayo Civic Center, where DFLers were gathered, was 20-year-old Tony Burton, of Minneapolis. He held a Klobuchar sign and has been interning for her campaign since January.

"She's really good at working across the aisle," Burton said. "She's been here for the last 12 years, and I believe she'll be here for the next six."

Star Tribune staff writer Judy Keen in Rochester also contributed to this story.