Buoyed by the Republican Party endorsement, Tom Emmer vowed Sunday to ramp up his campaign headed into the August primary for the congressional seat now held by Michele Bachmann.

Emmer, who lost a close 2010 governor's race to Mark Dayton, captured the party nod on the first ballot at Saturday's caucus, but two other GOP hopefuls said the endorsement process is not a good gauge of broad Republican support.

Rhonda Sivarajah, of Lino Lakes, chairwoman of the Anoka County Board, said she attended Saturday's Sixth District convention "out of respect for the people who were there," but said the process excludes many, including those working several jobs without time to go to conventions, people serving in the ­military, busy business owners and those who spend their spare time coaching or doing community volunteer work. She said she e-mailed the party officials a week before the convention to say she would run in the primary with or without the party endorsement.

Phil Krinkie, a state representative from Lino Lakes for 16 years and president of the Taxpayers League for seven years, said he didn't attend the convention because it would be hypocritical to do so when he already planned to run in the primary regardless of who was endorsed.

"I don't believe that 300-plus people are truly representative of the ­voters in the Sixth ­Congressional District," he said. He said the convention delegates are chosen "top-down" by party leaders rather than a grass-roots selection. "I believe in the process, but involvement is waning," he said.

Bachmann, a leader in the Tea Party Caucus, announced earlier this year she wouldn't seek a fifth term.

At least two DFL candidates also are seeking the seat and will compete in their party's May 3 convention.

Joe Perske, the Sartell mayor who is on leave from his teaching job, said he won't run in the primary without party endorsement. Another DFL candidate, Jim Read, of Avon, a political science professor at St. John's University and the College of St. ­Benedict, also said he would abide by the endorsement process.

Emmer, a lawyer and former state legislator from Delano, won 76 percent of about 350 delegate votes.

"We will expand the campaign. I have 6,000 individual donors; that is my base of people interested in our message," he said Sunday.

"I told the delegates Saturday that Republicans have to quit running against people and things and start offering solutions on economic issues and things people are concerned about," Emmer said.

"We have to be positive and working together. Republicans have a tendency to turn on each other."