Unlike any other recent US president, Donald Trump chose to make the mid-term elections personal. He went on the stump across the country in support of Republican candidates. Thus the Democrats are hailing their takeover of the House of Representatives as a defeat for a president that they and most of the American liberal elite loathe almost beyond reason.

But Trump has pointed out that he has actually been victorious because for only the sixth time in over a century, the incumbent’s party has actually increased the number of its legislators in the Senate. Moreover, Trump’s campaigning was largely confined to constituencies where Republican senators faced a tough contest or where new nominees were staging a viable challenge to a sitting Democrat. Thus, it seems that where the President focused on getting out the Republican vote, his presence did make a difference.

That ought to give Democrat leaders pause for thought. Despite Trump’s controversial record and what the political establishment insists is a dysfunctional and chaotic White House, there were clearly some smarts in this campaign. Trump has not received the crushing defeat that would have rendered winning a second term in 2020, completely unthinkable.

And Democrats ought anyway to have done better in line with the trend that has seen mid-term elections produce a vote against the sitting President’s party. Democrat chances of winning the White House in two years time depend very much on how they now use their control of the House. They have the power to block Trump’s legislation on the likes of immigration, the Mexican border wall, trade and the environment and will assuredly use it. The president can choose to try and make deals or more likely he will take the line of blaming Democrats for frustrating his chauvinistic and protectionist program which chimed with voters in 2016.

This would serve to deepen the already profound divisions in US politics, which have seen the legislature paralyzed by intractable budget disputes that have brought the nation close to technical bankruptcy. Will such a return of polarization hobble this most aggressive of presidents or will it empower his invective and bring back scathing references to the political “swamp” on Capitol Hill?

The crucial issue will be how House Democrats choose to use their investigatory powers to probe the alleged Russian interference in the 2016 elections, Trump’s financial affairs and alleged fraud by members of his administration. There is a strong push among Democrats to bring down this president one way or another through impeachment. If the House elects to take this route, it is likely to occupy much of its time in the coming 24 months. Trump will be able to argue that this is not a reasonable use of its legislative powers when the United States faces so many international and domestic challenges in terms of security, trade and political influence. Would House Democrats dare, for instance, to try and roll back the president’s resolute stance on Iran with all the dire consequences this would have for loyal US allies in the Middle East?

If Democrats choose to play the man rather than the ball, to go after the president rather than his policies, they must also consider the likely damage to the US political system and recognize the risk of further annoying an already frustrated electorate.