Rep. Justin AmashJustin AmashTrump, GOP at new crossroads on deficit Rand Paul revels in role of Senate troublemaker GOP lawmaker hits Trump over Dem memo: Americans deserve to read both MORE (R-Mich.) won't run for the Senate, ending months of speculation and clearing the way for former Michigan Secretary of State Terri Lynn Land (R) to be the GOP nominee.

A source close to Amash tells The Hill he has decided to forgo a bid.

Amash had long flirted with a potential bid but in recent weeks indicated he wasn't likely to run. The libertarian congressman said in late July that it would be "difficult" for any Republican to win the seat in the Democratic-leaning state, and the decision of regular ideological sparring partner, Rep. Mike Rogers (R-Mich.), not to run may have given Amash less incentive to run.

He's also carved out a niche as a leading civil libertarian in the House following his bipartisan push to defund the National Security Agency's domestic surveillance programs. That vote fell just short and helped him build his profile both nationally and within the House.

Land wasn't the GOP's first choice for the seat held by retiring Sen. Carl LevinCarl Milton LevinSen. Gillibrand, eyeing 2020 bid, rankles some Democrats The Hill's 12:30 Report Congress needs bipartisanship to fully investigate Russian influence MORE (R-Mich.) — national Republicans had hoped Rogers or Rep. Dave Camp (R-Mich.) would run. But recent polls show Land in a close race with Rep. Gary Peters (Mich.), the likely Democratic nominee. 

Neither is well known at this point, but the race could become competitive.