Rep. Todd Akin declared victory Tuesday evening in a hotly contested Missouri GOP Senate primary that featured a crowded field of candidates battling for a spot to face off against Democratic incumbent Sen. Claire McCaskill in November.

Akin faced businessman John Brunner and former state treasurer Sarah Steelman in the primary.

Going into Tuesday's contest, Brunner, a former manufacturing CEO and former Marine, had a fundraising advantage over his opponents, having raised $7.6 million this cycle, with a quarter-million coming from his own pocket.

Akin, a six-term U.S. congressman, touted his socially conservative values on the campaign trail, and gained the support of 2008 presidential candidate and former Arkansas Gov. Mike Huckabee. He was one of the first members of Congress to join the Tea Party Caucus in 2010 and has easily won re-election in recent years.

In his victory remarks, Akin thanked Huckabee, saying the former presidential candididate "stayed by our side, lifted us up in prayer, and tonight celebrates with us in victory."

The lawmaker raised a notable $2.2 million this cycle, as of July 18.

Steelman, who lagged far behind her competitors in terms of fund-raising, gained national attention in recent weeks after receiving the coveted endorsement of former Alaska Gov. Sarah Palin. The 2008 vice presidential nominee trumpeted Steelman as a reformer candidate at a picnic on Friday.

"Sarah was a 'Reaganite' before 'Reaganite' was cool, and that's what Washington needs more of today," Palin said.

Steelman, who once served in the state senate, also had the backing of the Tea Party Express.

One indication of how tight Tuesday's race was: Sen. McCaskill targeted all three GOP Senate hopefuls in attack ads last month. Republicans consider McCaskill, first elected in 2006, highly vulnerable in her re-election bid for a second term. A Mason-Dixon poll showed the senator falling behind each of the three main GOP competitors in hypothetical match-ups among registered Missouri voters.