As the title says, do politicians test new policies before executing them? I'm no politician - I have a scientific background - but I would personally want to simulate a policy against current law to determine any non-obvious caveats/loop holes/unwanted effects/illegal opportunities/etc. I'm sure software could be written to do this. Of course, software can never be the end-all, which is why we have political debates, etc. As I said I'm not a student of politics, so please forgive any ignorance! Maybe the whole thing is so complicated that only political debate is the answer...
This is probably the main function of the parliament. After all, in most democracies, the general policy direction is not really open to debate, it's defined by the platform of the party or parties that won a majority in the last elections, by coalition agreements and ultimately by the government implementing them. Except in very limited cases, the parliament is expected to go along with it until the next elections or change of government and what its members discuss are the details of the law.
You have to realize that in many cases, current bills include a long list of things like “Article so and so is modified to include this sentence” so simulating how it's going to fit in the current legislation (“consolidation”) is obviously necessary to make any sense of it.
Helping prepare the actual text of the bills is also what each MP's staff is supposed to do (even if in practice some of these positions are used either to pay for campaign staff or as a sinecure to reward friends and helpers or provide income to family members). Ministries/government departments also have legal staff to draft and review proposed legislation.
In some cases, there are additional procedures that are intended to provide extra checks of the quality of the law (in terms of not creating loopholes or inconsistencies). For example, in France, each new project has to be submitted to the conseil d'État (one of the highest courts in the country), which has a large staff of jurists in charge of advising the government on this. In Germany, the president can refuse to sign a law or refer it to the Federal constitutional court if he thinks there is a serious issue with it.
Beyond that, many countries have created consultative bodies to evaluate policies like the Congressional Budget Office in the US, the Office for Budget Responsibility in the UK, the Conseil économique, social et environnemental in France but they are mostly concerned with the economic impact of various policy choices and not so much with the formulation of the law itself.
Rarely will a politician favor a far-reaching policy that he would expect behave exactly as claimed, without some side-effects that would benefit the politician in question. Without access to a politician's confidential discussions it's not possible to know how the real objectives of a politician's policies compare with the stated objectives. Nonetheless, the pattern of:
- Opponents of a policy claim that if it is implemented, X will happen.
- Politician pushing the policy claims X won't happen.
- Opponents reiterate claim that it will.
- Policy is passed over objections.
- Lo and behold--X happens.
- Evidence is uncovered that reveals the proponent of the policy knew all along that X would happen, but wanted the policy for other reasons.
occurs so often that any time the first five parts of the pattern occur, it is reasonable to believe that the only reason the sixth doesn't is that the politician successfully concealed evidence of his knowledge.
In general, politicians favor policies which will give them political power. Their goal isn't to have policies that meet the claimed objectives; indeed, policies which appear to solve problems but have side-effects that actually make the problems worse, may offer greater political benefits than would policies that actually solved the problems they claimed to solve.
If one recognizes simple principles like "The total amount of ephemeral resource X that people will be able to afford cannot exceed the amount that is produced", one should not be surprised when, after a policy is introduced to make X more affordable to some people, many other people are no longer able to afford it. It's possible that politicians pushing such policies don't understand simple principles like the one above. A cynical person, however, might suspect that the purpose of the policy was not to help people, but rather to increase the number of people who would look to the politician for assistance.
In any case, politicians do "test" policies by conducting focus groups to try to ascertain how politically popular the policies will be; the actual performance of the policies, however, need not be tested since in many cases either the performance will be irrelevant, or the policies can be expected to yield results which are bad for the politicians' electorate, but good for the politician himself.
China's Mao did not test his policy. He started a Great Leap Forward and landed on his face. Between 15 to 45 million Chinese perished at his whim.
Deng Xiaoping learned Mao's lesson and switched to "crossing the river by feeling the stones." It took Deng more than a decade to experiment with his ideas. He started the reform in 1978, but it was not until 1992 that Deng began to have some confidence in what he was doing. The city of Shenzhen is famous for being one of the first special economic zones as a testing ground for Deng's policies.