When the fall sitting of parliament began in September, Justin Trudeau's Liberals enjoyed a comfortable lead in the polls and were on track for a re-elected majority government in 2019. Three months later, as parliament adjourns for the holidays, the Liberals find themselves back in the same position.

That doesn't mean it wasn't a bruising sitting for the Liberals, who dropped to their lowest level of support in the face of opposition questions targeting the ethics and tax plans of Finance Minister Bill Morneau. But whatever impact these attacks had on the Liberals' support, it appears to have largely dissipated.

With 39.6 per cent in the CBC Poll Tracker, the Liberals are down a little less than two points from where they stood when Parliament returned from the summer break on Sept. 18. The Conservatives follow with 32 per cent, up one point from the beginning of the sitting.

Both of these scores are within a tenth of a percentage point of where the two parties stood on election night in 2015.

The New Democrats are up less than a point to 16.6 per cent, with the Greens at 6.7 per cent and the Bloc Québécois at 4.2 per cent.

This relatively status quo sitting is unlike the first two of this parliamentary session. The first sitting at the beginning of 2016 saw Liberal support surge as the new government experienced a political honeymoon — the party went from 39.5 per cent in the 2015 election to 45.5 per cent support by the end of the spring of 2016.

Both the Conservatives, down more than three points, and the New Democrats, who fell nearly six points, felt the brunt of the Liberals' gains.

But during the fall 2016 sitting, the Liberal honeymoon was wearing off as the party's support slipped back 5.5 points and the opposition parties rebounded.

Since then, however, the 2017 sittings have not moved the dial significantly in any direction — though the New Democrats have yet to claw back all of the support, particularly in Quebec, that they lost to the Liberals in the months following the 2015 election.

Liberals rebound from fall lows

But if the dial has returned to its starting point, it did fluctuate throughout the year.

The margin between the Liberals and Conservatives decreased to just 3.1 points in the Poll Tracker on Oct. 17, when the Liberals had fallen to 35.9 per cent to 32.8 per cent for the Conservatives. At the time, the numbers suggested that the most likely outcome in a snap election would have been a Liberal minority, with a better than one-in-five chance of the Conservatives winning the most seats.

This dip came as questions about potential conflicts of interest concerning the finance minister and his family's firm were at their height. He committed to sell his shares in Morneau Shepell just two days later.

Since then, Liberal support has inched back upwards. If an election were held today, the Liberals would have a 96 per cent chance of winning, nearly identical to the probability of a Liberal victory on Sept. 18, and a 77 per cent chance of securing another majority government.

Little impact from Singh's win

While Andrew Scheer, installed as Conservative leader in May, has retained some of the modest gains he made in the weeks following his leadership victory — the party went from polling in the high-20s to the low-30s — there does not appear to have been much impact from the arrival of new NDP Leader Jagmeet Singh on the scene.

On Oct. 2, the day after Singh's first ballot leadership win, the NDP was at 16.3 per cent in the Poll Tracker. The party is now an insignificant 0.3 points higher.

The stagnation in the polls comes in the midst of the party's performance in federal byelections on Monday, in which support for NDP dropped in all four ridings where votes were held.

In Ottawa on Wednesday, Singh said that he didn't think he could "turn the ship around" in just two months. His predecessor, however, had more success. The NDP was averaging 29 per cent support in March 2012 when Tom Mulcair was named leader. Two months later, the party was at 35 per cent and leading in the polls.

Jack Layton and Alexa McDonough, the two NDP leaders before Mulcair, had little impact in the initial stages of their leaderships. But they also went on to win only 19 and 21 seats, respectively, in their first elections. These represented increases over the party's previous performances, but still less than half of the 44 seats the NDP currently holds.

Next year will be the first full year in which all opposition parties have their leaders in place (the Bloc Québécois selected Martine Ouellet in March). Elections in the country's two largest provinces will also be held. Both Scheer and Singh will have ample opportunity to move the dial more significantly in 2018, but they appear to have little to show for their efforts in 2017.