DFL insiders had hoped their nominee for governor would be settled by now, allowing the candidate to unify the party and get busy raising money and attacking former Gov. Tim Pawlenty, the Republican front-runner.

It was not to be, as state Rep. Erin Murphy won the hearts of party activists at the state DFL convention; U.S. Rep. Tim Walz pivoted toward the August primary, and Attorney General Lori Swanson jumped in at the last minute, creating a chaotic, expensive race that threatens to leave the winner broke and bruised.

But there's an upside: Republicans aren't sure whom to attack yet.

A GOP operative told me the muddled DFL field created a challenge for Republican ad makers who would like to go on the attack now. The lack of a clear target is especially problematic given the crowded ad landscape in the fall, when four competitive congressional races and two U.S. Senate contests will jam up the airwaves and drain cash from coffers of independent groups.

By contrast, the DFL side assumes Pawlenty will be the GOP nominee, and began attacking him on TV last week. The DFL-aligned Alliance for a Better Minnesota is spending big money on a 30-second spot featuring a woman who says Pawlenty's policies were bad for her disabled child.

Even if the DFL is pretty sure they'll be facing Pawlenty, the former two-term governor is taking no chances. His first ad, also released last week, is an attempt to bury his GOP opponent Jeff Johnson, the party's unsuccessful 2014 nominee. The ad tries to tar Johnson as a tax-and-spender. Johnson used a news conference, a radio appearance and social media to call the claims untrue, but he doesn't have the money to respond on TV, which is still considered the fastest and most effective way to reach a mass audience.

A Pawlenty adviser called the ad buy "significant."

Was Pawlenty's move a sign that Johnson was making inroads with Republican voters? Until he released the TV spot, Pawlenty rarely even uttered Johnson's name. Just as likely, a GOP operative told me, Pawlenty is being his old risk-averse self — leaving nothing to chance.

U.S. Rep. Erik Paulsen also dropped his opening ad last week. It illustrated that the Republican Paulsen, whose district includes the mostly western metro suburbs, knows he is in a very tough re-election environment.

The ad, which showed Paulsen in the Boundary Waters Canoe Area Wilderness, signaled that Paulsen knows that President Donald Trump is unpopular in his district, and that he faces the danger of a suburban anti-Trump wave. How do we know Trump is unpopular in the Third Congressional District? He lost the district to Hillary Clinton by more than 9 points, but Paulsen also confirmed it with his ad, in which the fifth-term congressman says, "I'll stand up to my party or President Donald Trump to protect Minnesota."

Paulsen's DFL opponent Dean Phillips scoffed, pointing to environmental groups' low regard for Paulsen.

J. Patrick Coolican 651-925-5042 Twitter: @jpcoolican patrick.coolican@startribune.com