First, I have not decided where I come out on dirty hands. I am leaning towards condemnation, but it is a very tricky situation. Second, I think you should assume in the example that we are in an anarchist political community where everyone legitimately consented to political institutions and unanimously decided upon democratic decision-making procedures. Third, I think there is a gap in your analysis, for you failed to mention the context in which the choice is presented. There is a second candidate who will win based on either a lie or a false belief, perhaps negligently false. So Candidate A is presented with a dilemma: either (1) tell the truth, but lose the election because Candidate B was willing to pander to irrationalities, or (2) lie, win the election and implement policies you truly believe will help the economy.
To better illustrate the dilemma, I will take the classic dirty hands example from Walzer.
We are now out of your ideal anarchist state. Assume you are a citizen in a country with particularly corrupt electoral practices (hard to imagine, I know). Big Business and Big Union pours illegal money into campaign finance in exchange for post-election benefits. Candidate A is an honest man and enters the arena with the promise to clean up the political scene. Soon after starting his campaign, he learns that, in order to win the election, he must make a deal with a corrupt union boss, which involves the granting of government contracts to pro-union corporations. Candidate A’s first instinct is: I can’t accept this offer. But he is told by his experienced campaign advisors that if you refuse, the money will go to Candidate B, a dishonest man, and we will have no evidence to prove what is going on. Worse, no one will believe us and the electorate will believe we are engaging in a smear campaign. So Candidate B will win the election and you will lose. You will never be in a position to start cleaning up the electoral process. So A’s choices are (1) reject the deal, and allow B to win and to continue the corrupt practices, or (2) accept the deal, gaining the chance to win. Is Candidate A permitted to take option (2)?