What happens when interest rates are at or near zero and governments are striving to boost economic?

Surely Central Banks are not privately owned institutions. In theory they are run independently from the Government & political parties/Parliament but they are public institutions. Their mission is to enable economic growth whilst preserving macro-economic stability. This can sometimes conflict with the Government agendas especially during the election years when the latter are tempted to employ populist measures to facilitate the leading party re-election and therefore the relationship between the two may be tensed from time to time, but rarely, as the National Bank is independent just in theory. Normally the Governments will go for measures as tax reduction on companies to boost activity or tax reduction on/and individuals to boost consumption. They have many other tools at hand: granting incentives and subsidies, employing large Gouverment projects in infrastructure or elsewhere. Normally this leads to an increased public debt that would be fueled by the low interest rates (which also aim to boost activity and/or consumption). Depending on how the measures are correlated and on the speed of slowing down when the economy starts to fly these measures combined can lead to inflation - the debt must be repaid and in case that tax collections will not increase significantly they will need to print money; as the consumption takes off this can put pressures on prices. More, if the consumption takes off, the economy is an import economy and the National Bank prints money to pay back the debt, the parity of the national currency will go down putting additional pressure on the price of imported goods. And this is how the wheel goes on and... down. But this does not work all the time - see Japan. When the deflationary expectation of the people becomes a social norm it seems difficult for these old economics to work. Possibly the financial crisis changed the consumerist paradigm.