He graduates from school with Os in all his NEWTs and chooses to start auror training because dark wizards are appearing with increased frequency so here lies his future success.
(it never occurs to him what he might do if these dark wizards became powerful enough to become the ministry's new rulers, and even if it did, he is too much of a believer in authority to think it's even humanely possible)
When his colleagues, Frank and Alice Longbottom, are found tortured so badly that they no longer know who they are, he is part of the team sent to arrest the culprits, and is delighted when he personally subdues Rabastan Lestrange using the imperius curse, as this will definitely aid his assent within the office, and he thinks yeah, maybe the imperius curse isn't morally right, but if Bartemius Crouch has authorised it, it must be necessary.
(it doesn't occur to him that maybe the real source of his happiness should be that he has removed a dangerous wizard from the streets. also a shame is that he's never really considered the effects dark magic tends to have on its own user)
When Harry Potter tells the world 'he' is back, and his boss Cornelius Fudge says Potter is a mentally unstable liar, he knows who he believes: dead men don't come back to life, and it just can't be true after all these years of peace. A part of his brain wonders whether there may be some truth to Potter's statements, but that part is quickly shot down: he won't even contemplate his wife and daughter being in danger.
(maybe the real solution would be to consider the old saying that planning and preparation prevents piss poor performance)
He follows every order that comes his way the following year: to tail Rubeus Hagrid, to arrest Albus Dumbledore etc. because surely the minister of magic himself must be right that these subversive elements seek to overthrow the ministry. He is not, unfortunately, successful in any of these endeavours.
(when the Lestranges and other dark wizards he fought against years ago break out from Azkaban, he swallows the official version about their acting under Sirius Black's leadership, not wondering how it would actually be possible for Black to stage Azkaban's first ever mass breakout without powerful backup.)
When the truth of the Dark Lord's return becomes known and Fudge is due to be replaced by Dawlish's own superior, Rufus Scrimgeour, Dawlish for once seriously contemplates: how can a schoolboy and the headmaster of a school be right where his superiors are wrong?
(not that this contemplation lasts long what with everything to do.)
When Scrimgeour dies and the Death Eaters become the ministry's new rulers, he goes with the flow because that's the way things are now and he has too much to lose if he refuses. When orders come to raid this house to see if Harry Potter is there, or to move that mudblood to Azkaban, he complies.
(he also has noticed how many of his colleagues in the auror office have died, been locked up, or else are on the wanted lists, and shudders to think what'll happen to him and his family if he resists the new rulers.)
He is recovering in St Mungo's from a failed arrest when he hears news of the Dark Lord's fall, shortly after which, a colleague from the auror office who'd been on the wanted lists arrives to Inform him he is under arrest.
(he hopes he will be able to argue he'd only been following orders, but that hope is dashed when he finds out an old colleague from the Auror Office, Kingsley Shacklebolt, is acting minister.)
"I was worried for my family's safety, and so I just did what I was told", he tells Shacklebolt when he answers to charges of intimidation, abuse of power, false imprisonment, kidnap and collaboration with the Dark Lord's regime. "Well that's not an excuse any more", answers Shacklebolt.
(as Dawlish is sentenced to forty years in prison, he realises for the first time it was all for nothing: it's the end of his career and he might well be dead before he can even get out to see his family again. following orders has failed him for the first time, and maybe, he thinks, it was bound to.)