Now that we're 34 games into Brad Childress' tenure and 16 starts into Tarvaris Jackson's career, now that Childress and the Vikings front office have built an impressive roster and raised expectations through the Teflon roof, we have to ask an impertinent question.

What's changed?

The Vikings' stunning loss to the Colts on Sunday leaves Childress 14-20 as a head coach. In the 34 games before Childress arrived, Mike Tice went 18-16 and won a road playoff game with fewer good players.

In Childress' first season, when he had Brad Johnson throwing to Travis Taylor and Marcus Robinson, the Vikings' passing game was among the worst in the NFL.

In his second season, with his handpicked quarterback project in place, the Vikings' passing game was among the worst in the NFL.

Now, two games into a promising season, with Jackson supposedly ready to make the step from erratic to efficient, the Vikings' passing game is among the worst in the NFL.

It is the inability to play catch that has cost the Vikings two winnable games, that has squandered a powerful running game, that has wasted two not-great-but-good-enough performances by the defense.

Jackson was awful Sunday, and it was his misfortune to play the same position in the same building as a great quarterback who enjoyed none of Jackson's advantages.

The game played out almost like a football experiment.

Let's take a Hall of Fame quarterback, give him a few quality receivers and see if he can win, on the road, with little help from the offensive line, running game and rushing defense. Let's even have the kicker shank a field goal just to raise his blood pressure.

On the other sideline, let's give a struggling quarterback a powerful running game, a dominating performance by the defensive front seven, a significant home field advantage, and see if he can win.

He couldn't. The Vikings' inability to complete meaningful forward passes led to their implosion and one of their worst losses in memory.

Jackson continues to miss his receivers by embarrassing margins. The receivers continue to fail to separate themselves from defensive backs. Tight end Visanthe Shiancoe continues to resemble Troy Williamson, without the speed.

Three years after bringing his run-oriented version of the West Coast offense to Minnesota, Childress' best passing combination remains the moderately productive one he dismissed after one season -- Johnson to Taylor.

The Colts and Vikings built their rosters in completely different manners. The Colts bottomed out and used the first pick in the 1998 draft on Peyton Manning, then built an entire franchise around him, giving him wonderful coaching, top-notch receivers, capable backs, an offense that suits his strengths, and a head coach who can find ways of putting together strong defenses out of spare parts.

The Vikings have amassed impressive players at almost every position other than quarterback and receiver, hoping Jackson could learn on the job and, as they say, "manage the game."

Here's the problem with "managing the game": Unless your defense is scoring touchdowns every week, eventually the quarterback will have to make a quality play to beat a good team. Jackson couldn't do that Sunday. He couldn't do it Monday in Green Bay. He didn't do it the last two weeks of last season with a playoff berth on the line.

Jackson has Adrian Peterson churning out yards and commanding the attention of the defense. He also has a four-game losing streak.

After the game, you could hear a Viking or two yelling in the locker room, and you could see Childress at Jackson's locker, teaching away.

This is the combination, the relationship, that will determine the Vikings' fate. If Childress and Jackson can find a way to move the ball through the air, two early losses shouldn't keep the Vikings out of the playoffs. If what we have seen through 34 games with Childress and 16 with Jackson proves to be indicative of their abilities, then the Vikings have wasted a lot of money, and a lot of optimism, on this season.

Until Sunday, I bought what Childress was selling -- that Jackson would be good enough to take advantage of the Vikings' many advantages.

So far, that hasn't been close to the truth. If Jackson plays like this for even a couple more weeks, the Vikings will look back on 2007 and 2008 as seasons they wasted on the wrong quarterback.

Jim Souhan can be heard Sundays from 10 a.m.-noon on AM-1500 KSTP •