This has been a significant week in Parliament.
On Monday the Government launched a new national security strategy that will help us to deal with a range of threats to the UK - anything from terrorism and war to national disasters such as floods and pandemics.
It's the first duty of any government to keep its citizens safe.
On Tuesday we published our Strategic Defence and Security Review. As the PM said in the Commons, Britain needs armed forces that are fit to meet the challenges of the 21st century.
But in the end strong defence can only be assured by a strong economy. So we cannot avoid defence playing its part in dealing with the deficit, not least because we inherited a £38 billion black hole in the Ministry of Defence budget from the last government.
As I write this article on Wednesday, George Osborne is unveiling the results of the Spending Review.
There will be significant cuts in public spending. The country cannot go on borrowing £1 for every £4 we spend. We face a budget deficit of £155 billion, one of the worst in Europe and the largest in our peacetime history.
If we failed to tackle this deficit, within five years we would be paying out £70 billion in debt interest a year - more than we spend on educating our children, policing our streets or defending our country.
And we would face higher interest rates, higher unemployment and then deeper cuts in the long run. We have to restore confidence and get the economy moving again.
I do understand the concerns about cuts, particularly from those who work in our public services. Last week I addressed police staff and PCSOs at the UNISON Police Conference in Southport and we discussed these issues. I know that many of their members are worried.
But as I said to them, we are taking this action because it is our responsibility to put the public finances back on a sound footing and because we want to do the right thing for our country.
We have tried to be fair, protecting the lowest paid and shielding valued services as far as we can - especially the NHS, schools, the armed forces and the police.
But savings can and must be made while protecting frontline services. It is in our national interest to take the difficult decisions now.