Politicians are people who want power. Why else would someone play an incredibly dirty game where success was dependent on perpetrating lies and half-truths for only a modest salary? Further they want power more than others want power. Generally the people who achieve something are the ones who want it most - the ones who are prepared to give up the most to get it. This makes politicians the worst possible people for running a country.
This does not change from party to party. Politicians recognize that openly promoting a command economy is too unpalatable for their constituents, but they try to impose more and more rules and regulations on the population to try to control more and more aspects of the lives of those they rule - and use the word 'freedom' to promote the policies.
Consider the example of the proposal to fine Australian citizens $AU5000.00 for gambling on the Internet. Could there be a policy more self-defeating than financially punishing someone for punishing their families? Or taking money away from someone's family because they are taking money away from their family? Or perhaps they would seek to only impose the fine on those who could afford $5000, and therefore didn't actually have a problem with gambling? In which case what possible justification is there for the fine? This has nothing to do with helping people - it is simply about control.
Predicting the behavior of a politician is, in principle, easy. What is the course of action which will gain them the most power? Power in a democracy is votes, so the question becomes 'where are the most votes for this person at the next election', and that will be the best indication.
Few politicians have a long term view of politics - they are resigned to the notion that they have just a few tries at success. Like Olympic athletes who may only get one or two shots at Olympic gold before they are too old and off-peak, politicians will usually sacrifice everything to win the next election, because they often don't get another try.
They have short shelf-lives, and they tolerate this. They eventually outlive their usefulness, their past catches up with them - the dirty back-room deals, and they fall on their swords.
Long term politicians are far more scary. Some politicians refuse to make dirty back-room deals which may catch up for them because they take the long term view. They tend to stay in power a long time, and it is very hard to remove them.
Fortunately, politicians in a democracy do not really have a lot of power. They are merely the conduits for the wishes of the special interest groups they represent. This tends to limit the damage they can do to the (not insignificant) stupidity of their support base of minority groups.
A good model to predict behavior of politicians is
Money to fund a political campaign frequently comes from corporations (including unions), and this is repaid through corporate welfare or pro-union legislation.